BRATA Keeps Sneaking into Google Play, Now Targeting USA and Spain

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Recently, the McAfee Mobile Research Team uncovered several new variants of the Android malware family BRATA being distributed in Google Play, ironically posing as app security scanners.

These malicious apps urge users to update Chrome, WhatsApp, or a PDF reader, yet instead of updating the app in question, they take full control of the device by abusing accessibility services. Recent versions of BRATA were also seen serving phishing webpages targeting users of financial entities, not only in Brazil but also in Spain and the USA.

In this blog post we will provide an overview of this threat, how does this malware operates and its main upgrades compared with earlier versions. If you want to learn more about the technical details of this threat and the differences between all variants you can check the BRATA whitepaper here.

The origins of BRATA

First seen in the wild at the end of 2018 and named “Brazilian Remote Access Tool Android ” (BRATA) by Kaspersky, this “RAT” initially targeted users in Brazil and then rapidly evolved into a banking trojan. It combines full device control capabilities with the ability to display phishing webpages that steal banking credentials in addition to abilities that allow it capture screen lock credentials (PIN, Password or Pattern), capture keystrokes (keylogger functionality), and record the screen of the infected device to monitor a user’s actions without their consent.

Because BRATA is distributed mainly on Google Play, it allows bad actors to lure victims into installing these malicious apps pretending that there is a security issue on the victim’s device and asking to install a malicious app to fix the problem. Given this common ruse, it is recommended to avoid clicking on links from untrusted sources that pretend to be a security software which scans and updates your system—e even if that link leads to an app in Google Play. McAfee offers protection against this threat via McAfee Mobile Security, which detects this malware as Android/Brata.

How BRATA Android malware has evolved and targets new victims

The main upgrades and changes that we have identified in the latest versions of BRATA recently found in Google Play include:

  • Geographical expansion: Initially targeting Brazil, we found that recent variants started to also target users in Spain and the USA.
  • Banking trojan functionality: In addition to being able to have full control of the infected device by abusing accessibility services, BRATA is now serving phishing URLs based on the presence of certain financial and banking apps defined by the remote command and control server.
  • Self-defense techniques: New BRATA variants added new protection layers like string obfuscation, encryption of configuration files, use of commercial packers, and the move of its core functionality to a remote server so it can be easily updated without changing the main application. Some BRATA variants also check first if the device is worth being attacked before downloading and executing their main payload, making it more evasive to automated analysis systems.

BRATA in Google Play

During 2020, the threat actors behind BRATA have managed to publish several apps in Google Play, most of them reaching between one thousand to five thousand installs. However, also a few variants have reached 10,000 installs including the latest one, DefenseScreen, reported to Google by McAfee in October and later removed from Google Play.

Figure 1. DefenseScreen app in Google Play.

From all BRATA apps that were in Google Play in 2020, five of them caught our attention as they have notable improvements compared with previous ones. We refer to them by the name of the developer accounts:

Figure 2. Timeline of identified apps in Google Play from May to October 2020

Social engineering tricks

BRATA poses as a security app scanner that pretends to scan all the installed apps, while in the background it checks if any of the target apps provided by a remote server are installed in the user’s device. If that is the case, it will urge the user to install a fake update of a specific app selected depending on the device language. In the case of English-language apps, BRATA suggests the update of Chrome while also constantly showing a notification at the top of the screen asking the user to activate accessibility services:

Figure 3. Fake app scanning functionality

Once the user clicks on “UPDATE NOW!”, BRATA proceeds to open the main Accessibility tab in Android settings and asks the user to manually find the malicious service and grant permissions to use accessibility services. When the user attempts to do this dangerous action, Android warns of the potential risks of granting access to accessibility services to a specific app, including that the app can observe your actions, retrieve content from Windows, and perform gestures like tap, swipe, and pinch.

As soon as the user clicks on OK the persistent notification goes away, the main icon of the app is hidden and a full black screen with the word “Updating” appears, which could be used to hide automated actions that now can be performed with the abuse of accessibility services:

Figure 4. BRATA asking access to accessibility services and showing a black screen to potentially hide automated actions

At this point, the app is completely hidden from the user, running in the background in constant communication with a command and control server run by the threat actors. The only user interface that we saw when we analyzed BRATA after the access to accessibility services was granted was the following screen, created by the malware to steal the device PIN and use it to unlock it when the phone is unattended. The screen asks the user to confirm the PIN, validating it with the real one because when an incorrect PIN is entered, an error message is shown and the screen will not disappear until the correct PIN is entered:

Figure 5. BRATA attempting to steal device PIN and confirming if the correct one is provided

BRATA capabilities

Once the malicious app is executed and accessibility permissions have been granted, BRATA can perform almost any action in the compromised device. Here’s the list of commands that we found in all the payloads that we have analyzed so far:

  • Steal lock screen (PIN/Password/Pattern)
  • Screen Capture: Records the device’s screen and sends screenshots to the remote server
  • Execute Action: Interact with user’s interface by abusing accessibility services
  • Unlock Device: Use stolen PIN/Password/Pattern to unlock the device
  • Start/Schedule activity lunch: Opens a specific activity provided by the remote server
  • Start/Stop Keylogger: Captures user’s input on editable fields and leaks that to a remote server
  • UI text injection: Injects a string provided by the remote server in an editable field
  • Hide/Unhide Incoming Calls: Sets the ring volume to 0 and creates a full black screen to hide an incoming call
  • Clipboard manipulation: Injects a string provided by the remote server in the clipboard

In addition to the commands above, BRATA also performs automated actions by abusing accessibility services to hide itself from the user or automatically grant privileges to itself:

  • Hides the media projection warning message that explicitly warns the user that the app will start capturing everything displayed on the screen.
  • Grants itself any permissions by clicking on the “Allow” button when the permission dialog appears in the screen.
  • Disables Google Play Store and therefore Google Play Protect.
  • Uninstalls itself in case that the Settings interface of itself with the buttons “Uninstall” and “Force Stop” appears in the screen.

Geographical expansion and Banking Trojan Functionality

Earlier BRATA versions like OutProtect and PrivacyTitan were designed to target Brazilian users only by limiting its execution to devices set to the Portuguese language in Brazil. However, in June we noticed that threat actors behind BRATA started to add support to other languages like Spanish and English. Depending on the language configured in the device, the malware suggested that one of the following three apps needed an urgent update: WhatsApp (Spanish), a non-existent PDF Reader (Portuguese) and Chrome (English):

Figure 6. Apps falsely asked to be updated depending on the device language

In addition to the localization of the user-interface strings, we also noticed that threat actors have updated the list of targeted financial apps to add some from Spain and USA. In September, the target list had around 52 apps but only 32 had phishing URLs. Also, from the 20 US banking apps present in the last target list only 5 had phishing URLs. Here’s an example of phishing websites that will be displayed to the user if specific US banking apps are present in the compromised device:

Figure 7. Examples of phishing websites pretending to be from US banks

Multiple Obfuscation Layers and Stages

Throughout 2020, BRATA constantly evolved, adding different obfuscation layers to impede its analysis and detection. One of the first major changes was moving its core functionality to a remote server so it can be easily updated without changing the original malicious application. The same server is used as a first point of contact to register the infected device, provide an updated list of targeted financial apps, and then deliver the IP address and port of the server that will be used by the attackers to execute commands remotely on the compromised device:

 

Figure 8. BRATA high level network communication

Additional protection layers include string obfuscation, country and language check, encryption of certain key strings in assets folder, and, in latest variants, the use of a commercial packer that further prevents the static and dynamic analysis of the malicious apps. The illustration below provides a summary of the different protection layers and execution stages present in the latest BRATA variants:

Figure 9. BRATA protection layers and execution stages

Prevention and defense

In order get infected with BRATA ,users must install the malicious application from Google Play so below are some recommendations to avoid being tricked by this or any other Android threats that use social engineering to convince users to install malware that looks legitimate:

  • Don’t trust an Android application just because it’s available in the official store. In this case, victims are mainly lured to install an app that promises a more secure device by offering a fake update. Keep in mind that in Android updates are installed automatically via Google Play so users shouldn’t require the installation of a third-party app to have the device up to date.
  • McAfee Mobile Security will alert users if they are attempting to install or execute a malware even if it’s downloaded from Google Play. We recommend users to have a reliable and updated antivirus installed on their mobile devices to detect this and other malicious applications.
  • Do not click on suspicious links received from text messages or social media, particularly from unknown sources. Always double check by other means if a contact that sends a link without context was really sent by that person, because it could lead to the download of a malicious application.
  • Before installing an app, check the developer information, requested permissions, the number of installations, and the content of the reviews. Sometimes applications could have very good rating but most of the reviews could be fake, such as we uncovered in Android/LeifAccess. Be aware that ranking manipulation happens and that reviews are not always trustworthy.

The activation of accessibility services is very sensitive in Android and key to the successful execution of this banking trojan because, once the access to those services is granted, BRATA can perform all the malicious activities and take control of the device. For this reason, Android users must be very careful when granting this access to any app.

Accessibility services are so powerful that in hands of a malicious app they could be used to fully compromise your device data, your online banking and finances, and your digital life overall.

BRATA Android malware continues to evolve—another good reason for protecting mobile devices

When BRATA was initially discovered in 2019 and named “Brazilian Android RAT” by Kaspersky, it was said that, theoretically, the malware can be used to target other users if the cybercriminals behind this threat wanted to do it. Based on the newest variants found in 2020, the theory has become reality, showing that this threat is currently very active, constantly adding new targets, new languages and new protection layers to make its detection and analysis more difficult.

In terms of functionality, BRATA is just another example of how powerful the (ab)use of accessibility services is and how, with just a little bit of social engineering and persistence, cybercriminals can trick users into granting this access to a malicious app and basically getting total control of the infected device. By stealing the PIN, Password or Pattern, combined with the ability to record the screen, click on any button and intercept anything that is entered in an editable field, malware authors can virtually get any data they want, including banking credentials via phishing web pages or even directly from the apps themselves, while also hiding all these actions from the user.

Judging by our findings, the number of apps found in Google Play in 2020 and the increasing number of targeted financial apps, it looks like BRATA will continue to evolve, adding new functionality, new targets, and new obfuscation techniques to target as many users as possible, while also attempting to reduce the risk of being detected and removed from the Play store.

McAfee Mobile Security detects this threat as Android/Brata. To protect yourselves from this and similar threats, employ security software on your mobile devices and think twice before granting access to accessibility services to suspicious apps, even if they are downloaded from trusted sources like Google Play.

Appendix

Techniques, Tactics and Procedures (TTPS)

Figure 10. MITRE ATT&CK Mobile for BRATA

<h3>Indicators of compromise

Apps:

SHA256 Package Name Installs
4cdbd105ab8117620731630f8f89eb2e6110dbf6341df43712a0ec9837c5a9be com.outprotect.android 1,000+
d9bc87ab45b0c786aa09f964a8101f6df7ea76895e2e8438c13935a356d9116b com.privacytitan.android 1,000+
f9dc40a7dd2a875344721834e7d80bf7dbfa1bf08f29b7209deb0decad77e992 com.greatvault.mobile 10,000+
e00240f62ec68488ef9dfde705258b025c613a41760138b5d9bdb2fb59db4d5e com.pw.secureshield 5,000+
2846c9dda06a052049d89b1586cff21f44d1d28f153a2ff4726051ac27ca3ba7 com.defensescreen.application 10,000+

 

URLs:

  • bialub[.]com
  • brorne[.]com
  • jachof[.]com

 

Technical Analysis of BRATA Apps

This paper will analyze five different “Brazilian Remote Access Tool Android” (BRATA) apps found in Google Play during 2020.

View Now

The post BRATA Keeps Sneaking into Google Play, Now Targeting USA and Spain appeared first on McAfee Blogs.

McAfee ATR Threat Report: A Quick Primer on Cuba Ransomware

Executive Summary 

Cuba ransomware is an older ransomware, that has recently undergone some development. The actors have incorporated the leaking of victim data to increase its impact and revenue, much like we have seen recently with other major ransomware campaigns. 

In our analysis, we observed that the attackers had access to the network before the infection and were able to collect specific information in order to orchestrate the attack and have the greatest impact. The attackers operate using a set of PowerShell scripts that enables them to move laterally. The ransom note mentions that the data was exfiltrated before it was encrypted. In similar attacks we have observed the use of Cobalt Strike payload, although we have not found clear evidence of a relationship with Cuba ransomware. 

We observed Cuba ransomware targeting financial institutions, industry, technology and logistics organizations.  

The following picture shows an overview of the countries that have been impacted according to our telemetry.  

Coverage and Protection Advice 

Defenders should be on the lookout for traces and behaviours that correlate to open source pen test tools such as winPEASLazagne, Bloodhound and Sharp Hound, or hacking frameworks like Cobalt Strike, Metasploit, Empire or Covenant, as well as abnormal behavior of non-malicious tools that have a dual use. These seemingly legitimate tools (e.g., ADfindPSExec, PowerShell, etc.) can be used for things like enumeration and execution. Subsequently, be on the lookout for abnormal usage of Windows Management Instrumentation WMIC (T1047). We advise everyone to check out the following blogs on evidence indicators for a targeted ransomware attack (Part1Part2).  

Looking at other similar Ransomware-as-a-Service families we have seen that certain entry vectors are quite common among ransomware criminals: 

  • E-mail Spear phishing (T1566.001) often used to directly engage and/or gain an initial foothold. The initial phishing email can also be linked to a different malware strain, which acts as a loader and entry point for the attackers to continue completely compromising a victim’s network. We have observed this in the past with the likes of Trickbot & Ryuk or Qakbot & Prolock, etc.  
  • Exploit Public-Facing Application (T1190) is another common entry vector, given cyber criminals are often avid consumers of security news and are always on the lookout for a good exploit. We therefore encourage organizations to be fast and diligent when it comes to applying patches. There are numerous examples in the past where vulnerabilities concerning remote access software, webservers, network edge equipment and firewalls have been used as an entry point.  
  • Using valid accounts (T1078) is and has been a proven method for cybercriminals to gain a foothold. After all, why break the door down if you already have the keys? Weakly protected RDP access is a prime example of this entry method. For the best tips on RDP security, please see our blog explaining RDP security. 
  • Valid accounts can also be obtained via commodity malware such as infostealers that are designed to steal credentials from a victim’s computer. Infostealer logs containing thousands of credentials can be purchased by ransomware criminals to search for VPN and corporate logins. For organizations, having a robust credential management and MFA on user accounts is an absolute must have.  

When it comes to the actual ransomware binary, we strongly advise updating and upgrading endpoint protection, as well as enabling options like tamper protection and Rollback. Please read our blog on how to best configure ENS 10.7 to protect against ransomware for more details. 

For active protection, more details can be found on our website –  https://www.mcafee.com/enterprise/en-us/threat-center/threat-landscape-dashboard/ransomware-details.cuba-ransomware.html – and in our detailed Defender blog. 

Summary of the Threat 

  • Cuba ransomware is currently hitting several companies in north and south America, as well as in Europe.  
  • The attackers use a set of obfuscated PowerShell scripts to move laterally and deploy their attack.  
  • The website to leak the stolen data has been put online recently.  
  • The malware is obfuscated and comes with several evasion techniques.  
  • The actors have sold some of the stolen data 
  • The ransomware uses multiple argument options and has the possibility to discover shared resources using the NetShareEnum API. 

Learn more about Cuba ransomware, Yara Rules, Indicators of Compromise & Mitre ATT&CK techniques used by reading our detailed technical analysis.

The post McAfee ATR Threat Report: A Quick Primer on Cuba Ransomware appeared first on McAfee Blogs.

McAfee Defender’s Blog: Cuba Ransomware Campaign

Cuba Ransomware Overview

Over the past year, we have seen ransomware attackers change the way they have responded to organizations that have either chosen to not pay the ransom or have recovered their data via some other means. At the end of the day, fighting ransomware has resulted in the bad actors’ loss of revenue. Being the creative bunch they are, they have resorted to data dissemination if the ransom is not paid. This means that significant exposure could still exist for your organization, even if you were able to recover from the attack.

Cuba ransomware, no newcomer to the game, has recently introduced this behavior.

This blog is focused on how to build an adaptable security architecture to increase your resilience against these types of attacks and specifically, how McAfee’s portfolio delivers the capability to prevent, detect and respond against the tactics and techniques used in the Cuba Ransomware Campaign.

Gathering Intelligence on Cuba Ransomware

As always, building adaptable defensive architecture starts with intelligence. In most organizations, the Security Operations team is responsible for threat intelligence analysis, as well as threat and incident response. McAfee Insights (https://www.mcafee.com/enterprise/en-us/lp/insights-dashboard1.html#) is a great tool for the threat intel analyst and threat responder. The Insights Dashboard identifies prevalence and severity of emerging threats across the globe which enables the Security Operations Center (SOC) to prioritize threat response actions and gather relevant cyber threat intelligence (CTI) associated with the threat, in this case the Cuba ransomware campaign. The CTI is provided in the form of technical indicators of compromise (IOCs) as well as MITRE ATT&CK framework tactics and techniques. As a threat intel analyst or responder you can drill down to gather more specific information on Cuba ransomware, such as prevalence and links to other sources of information. You can further drill down to gather more specific actionable intelligence such as indicators of compromise and tactics/techniques aligned to the MITRE ATT&CK framework.

From the McAfee Advanced Threat Research (ATR) blog, you can see that Cuba ransomware leverages tactics and techniques common to other APT campaigns. Currently, the Initial Access vector is not known. It could very well be spear phishing, exploited system tools and signed binaries, or a multitude of other popular methods.

Defensive Architecture Overview

Today’s digital enterprise is a hybrid environment of on-premise systems and cloud services with multiple entry points for attacks like Cuba ransomware. The work from home operating model forced by COVID-19 has only expanded the attack surface and increased risk for successful spear phishing attacks if organizations did not adapt their security posture and increase training for remote workers. Mitigating the risk of attacks like Cuba ransomware requires a security architecture with the right controls at the device, on the network and in security operations (SecOps). The Center for Internet Security (CIS) Top 20 Cyber Security Controls provides a good guide to build that architecture. As indicated earlier, the exact entry vector used by Cuba ransomware is currently unknown, so what follows, here, are more generalized recommendations for protecting your enterprise.

Initial Access Stage Defensive Overview

According to Threat Intelligence and Research, the initial access for Cuba ransomware is not currently known. As attackers can leverage many popular techniques for initial access, it is best to validate efficacy on all layers of defenses. This includes user awareness training and response procedures, intelligence and behavior-based malware defenses on email systems, web proxy and endpoint systems, and finally SecOps playbooks for early detection and response against suspicious email attachments or other phishing techniques. The following chart summarizes the controls expected to have the most effect against initial stage techniques and the McAfee solutions to implement those controls where applicable.

MITRE Tactic MITRE Techniques CSC Controls McAfee Capability
Initial Access Spear Phishing Attachments (T1566.001) CSC 7 – Email and Web Browser Protection

CSC 8 – Malware Defenses

CSC 17 – User Awareness

Endpoint Security Platform 10.7, Threat Prevention, Adaptive Threat Protection,

Web Gateway (MWG), Advanced Threat Defense, Web Gateway Cloud Service (WGCS)

Initial Access Spear Phishing Link (T1566.002) CSC 7 – Email and Web Browser Protection

CSC 8 – Malware Defenses

CSC 17 – User Awareness

Endpoint Security Platform 10.7, Threat Prevention, Adaptive Threat Protection,

Web Gateway (MWG), Advanced Threat Defense, Web Gateway Cloud Service (WGCS)

Initial Access Spear Phishing (T1566.003) Service CSC 7 – Email and Web Browser Protection

CSC 8 – Malware Defenses

CSC 17 – User Awareness

Endpoint Security Platform 10.7, Threat Prevention, Adaptive Threat Protection,

Web Gateway (MWG), Advanced Threat Defense, Web Gateway Cloud Service (WGCS)

For additional information on how McAfee can protect against suspicious email attachments, review this additional blog post: https://www.mcafee.com/blogs/other-blogs/mcafee-labs/mcafee-protects-against-suspicious-email-attachments/

Exploitation Stage Defensive Overview

The exploitation stage is where the attacker gains access to the target system. Protection against Cuba ransomware at this stage is heavily dependent on adaptable anti-malware on both end user devices and servers, restriction of application execution, and security operations tools like endpoint detection and response sensors.

McAfee Endpoint Security 10.7 provides a defense in depth capability, including signatures and threat intelligence, to cover known bad indicators or programs, as well as machine-learning and behavior-based protection to reduce the attack surface against Cuba ransomware and detect new exploitation attack techniques. If the initial entry vector is a weaponized Word document with links to external template files on a remote server, for example, McAfee Threat Prevention and Adaptive Threat Protection modules protect against these techniques.

The following chart summarizes the critical security controls expected to have the most effect against exploitation stage techniques and the McAfee solutions to implement those controls where applicable.

MITRE Tactic MITRE Techniques CSC Controls McAfee Portfolio Mitigation
Execution User Execution (T1204) CSC 5 Secure Configuration

CSC 8 Malware Defenses

CSC 17 Security Awareness

Endpoint Security Platform 10.7, Threat Prevention, Adaptive Threat Protection, Application Control (MAC), Web Gateway and Network Security Platform
Execution Command and Scripting Interpreter (T1059)

 

CSC 5 Secure Configuration

CSC 8 Malware Defenses

Endpoint Security Platform 10.7, Threat Prevention, Adaptive Threat Protection, Application Control (MAC), MVISION EDR
Execution Shared Modules (T1129) CSC 5 Secure Configuration

CSC 8 Malware Defenses

Endpoint Security Platform 10.7, Threat Prevention, Adaptive Threat Protection, Application Control (MAC)
Persistence Boot or Autologon Execution (T1547) CSC 5 Secure Configuration

CSC 8 Malware Defenses

Endpoint Security Platform 10.7 Threat Prevention, MVISION EDR
Defensive Evasion Template Injection (T1221) CSC 5 Secure Configuration

CSC 8 Malware Defenses

Endpoint Security Platform 10.7, Threat Prevention, Adaptive Threat Protection, MVISION EDR
Defensive Evasion Signed Binary Proxy Execution (T1218) CSC 4 Control Admin Privileges

CSC 5 Secure Configuration

CSC 8 Malware Defenses

Endpoint Security Platform 10.7, Threat Prevention, Adaptive Threat Protection, Application Control, MVISION EDR
Defensive Evasion Deobfuscate/Decode Files or Information (T1027)

 

CSC 5 Secure Configuration

CSC 8 Malware Defenses

Endpoint Security Platform 10.7, Threat Prevention, Adaptive Threat Protection, MVISION EDR

For more information on how McAfee Endpoint Security 10.7 can prevent some of the techniques used in the Cuba ransomware exploit stage, review this additional blog post: https://www.mcafee.com/blogs/other-blogs/mcafee-labs/mcafee-amsi-integration-protects-against-malicious-scripts/

Impact Stage Defensive Overview

The impact stage is where the attacker encrypts the target system, data and perhaps moves laterally to other systems on the network. Protection at this stage is heavily dependent on adaptable anti-malware on both end user devices and servers, network controls and security operation’s capability to monitor logs for anomalies in privileged access or network traffic. The following chart summarizes the controls expected to have the most effect against impact stage techniques and the McAfee solutions to implement those controls where applicable:

The public leak site of Cuba ransomware can be found via TOR: http://cuba4mp6ximo2zlo[.]onion/

MITRE Tactic MITRE Techniques CSC Controls McAfee Portfolio Mitigation
Discovery Account Discovery (T1087) CSC 4 Control Use of Admin Privileges

CSC 5 Secure Configuration

CSC 6 Log Analysis

MVISION EDR, MVISION Cloud, Cloud Workload Protection
Discovery System Information Discovery (T1082) CSC 4 Control Use of Admin Privileges

CSC 5 Secure Configuration

CSC 6 Log Analysis

MVISION EDR, MVISION Cloud, Cloud Workload Protection
Discovery System Owner/User Discovery (T1033) CSC 4 Control Use of Admin Privileges

CSC 5 Secure Configuration

CSC 6 Log Analysis

MVISION EDR, MVISION Cloud, Cloud Workload Protection
Command and Control Encrypted Channel (T1573) CSC 8 Malware Defenses

CSC 12 Boundary Defenses

Web Gateway, Network Security Platform

 

Hunting for Cuba Ransomware Indicators

As a threat intel analyst or hunter, you might want to quickly scan your systems for any indicators you received on Cuba ransomware. Of course, you can do that manually by downloading a list of indicators and searching with available tools. However, if you have MVISION EDR and Insights, you can do that right from the console, saving precious time. Hunting the attacker can be a game of inches so every second counts. Of course, if you found infected systems or systems with indicators, you can take action to contain and start an investigation for incident response immediately from the MVISION EDR console.

In addition to these IOCs, YARA rules are available in our technical analysis of Cuba ransomware.

IOCs:

Files:

151.bat

151.ps1

Kurva.ps1

 

Email addresses:

[email protected][.]ch

[email protected][.]li

[email protected][.]com

[email protected][.]ch

[email protected]

[email protected]

[email protected]

 

Domain:

kurvalarva[.]com

 

Script for lateral movement and deployment:

54627975c0befee0075d6da1a53af9403f047d9e367389e48ae0d25c2a7154bc

c385ef710cbdd8ba7759e084051f5742b6fa8a6b65340a9795f48d0a425fec61

40101fb3629cdb7d53c3af19dea2b6245a8d8aa9f28febd052bb9d792cfbefa6

 

Cuba Ransomware:

c4b1f4e1ac9a28cc9e50195b29dde8bd54527abc7f4d16899f9f8315c852afd4

944ee8789cc929d2efda5790669e5266fe80910cabf1050cbb3e57dc62de2040
78ce13d09d828fc8b06cf55f8247bac07379d0c8b8c8b1a6996c29163fa4b659
33352a38454cfc247bc7465bf177f5f97d7fd0bd220103d4422c8ec45b4d3d0e

672fb249e520f4496e72021f887f8bb86fec5604317d8af3f0800d49aa157be1
e942a8bcb3d4a6f6df6a6522e4d5c58d25cdbe369ecda1356a66dacbd3945d30

907f42a79192a016154f11927fbb1e6f661f679d68947bddc714f5acc4aa66eb
28140885cf794ffef27f5673ca64bd680fc0b8a469453d0310aea439f7e04e64
271ef3c1d022829f0b15f2471d05a28d4786abafd0a9e1e742bde3f6b36872ad
6396ea2ef48aa3d3a61fb2e1ca50ac3711c376ec2b67dbaf64eeba49f5dfa9df

bda4bddcbd140e4012bab453e28a4fba86f16ac8983d7db391043eab627e9fa1

7a17f344d916f7f0272b9480336fb05d33147b8be2e71c3261ea30a32d73fecb

c206593d626e1f8b9c5d15b9b5ec16a298890e8bae61a232c2104cbac8d51bdd

9882c2f5a95d7680626470f6c0d3609c7590eb552065f81ab41ffe074ea74e82

c385ef710cbdd8ba7759e084051f5742b6fa8a6b65340a9795f48d0a425fec61
54627975c0befee0075d6da1a53af9403f047d9e367389e48ae0d25c2a7154bc
1f825ef9ff3e0bb80b7076ef19b837e927efea9db123d3b2b8ec15c8510da647
40101fb3629cdb7d53c3af19dea2b6245a8d8aa9f28febd052bb9d792cfbefa6

00ddbe28a31cc91bd7b1989a9bebd43c4b5565aa0a9ed4e0ca2a5cfb290475ed

729950ce621a4bc6579957eabb3d1668498c805738ee5e83b74d5edaf2f4cb9e

 

MITRE ATT&CK Techniques:

Tactic Technique Observable IOCs
Execution Command and Scripting Interpreter: PowerShell (T1059.001) Cuba team is using PowerShell payload to drop Cuba ransomware f739977004981fbe4a54bc68be18ea79

68a99624f98b8cd956108fedcc44e07c

bdeb5acc7b569c783f81499f400b2745

 

Execution System Services: Service Execution (T1569.002)  

 

Execution Shared Modules (T1129) Cuba ransomware links function at runtime Functions:

“GetModuleHandle”

“GetProcAddress”

“GetModuleHandleEx”

Execution Command and Scripting Interpreter (T1059) Cuba ransomware accepts command line arguments Functions:

“GetCommandLine”

Persistence Create or Modify System Process: Windows Service (T1543.003) Cuba ransomware can modify services Functions:

“OpenService”

“ChangeServiceConfig”

Privilege Escalation Access Token Manipulation (T1134) Cuba ransomware can adjust access privileges Functions:

“SeDebugPrivilege”

“AdjustTokenPrivileges”

“LookupPrivilegeValue”

Defense Evasion File and Directory Permissions Modification (T1222) Cuba ransomware will set file attributes Functions:

“SetFileAttributes”

Defense Evasion Obfuscated files or Information (T1027) Cuba ransomware is using xor algorithm to encode data
Defense Evasion Virtualization/Sandbox Evasion: System Checks Cuba ransomware executes anti-vm instructions
Discovery File and Directory Discovery (T1083) Cuba ransomware enumerates files Functions:

“FindFirstFile”

“FindNextFile”

“FindClose”

“FindFirstFileEx”

“FindNextFileEx”

“GetFileSizeEx”

Discovery Process Discovery (T1057) Cuba ransomware enumerates process modules Functions:

“K32EnumProcesses”

Discovery System Information Discovery (T1082) Cuba ransomware can get keyboard layout, enumerates disks, etc Functions:

“GetKeyboardLayoutList”

“FindFirstVolume”

“FindNextVolume”

“GetVolumePathNamesForVolumeName”

“GetDriveType”

“GetLogicalDriveStrings”

“GetDiskFreeSpaceEx”

Discovery System Service Discovery (T1007) Cuba ransomware can query service status Functions:

“QueryServiceStatusEx”

Collection Input Capture: Keylogging (T1056.001) Cuba ransomware logs keystrokes via polling Functions:

“GetKeyState”

“VkKeyScan”

Impact Service Stop (T1489) Cuba ransomware can stop services
Impact Data encrypted for Impact (T1486) Cuba ransomware encrypts data

 

Proactively Detecting Cuba Ransomware Techniques

Many of the exploit stage techniques in this attack could use legitimate Windows processes and applications to either exploit or avoid detection. We discussed, above, how the Endpoint Protection Platform can disrupt weaponized documents but, by using MVISION EDR, you can get more visibility. As security analysts, we want to focus on suspicious techniques used by Initial Access, as this attack’s Initial Access is unknown.

Monitoring or Reporting on Cuba Ransomware Events

Events from McAfee Endpoint Protection and McAfee MVISION EDR play a key role in Cuba ransomware incident and threat response. McAfee ePO centralizes event collection from all managed endpoint systems. As a threat responder, you may want to create a dashboard for Cuba ransomware-related threat events to understand your current exposure.

Summary

To defeat targeted threat campaigns, defenders must collaborate internally and externally to build an adaptive security architecture which will make it harder for threat actors to succeed and build resilience in the business. This blog highlights how to use McAfee’s security solutions to prevent, detect and respond to Cuba ransomware and attackers using similar techniques.

McAfee ATR is actively monitoring this campaign and will continue to update McAfee Insights and its social networking channels with new and current information. Want to stay ahead of the adversaries? Check out McAfee Insights for more information.

The post McAfee Defender’s Blog: Cuba Ransomware Campaign appeared first on McAfee Blogs.

McAfee Defenders Blog: Reality Check for your Defenses

ウイルススキャン Uirususukyan

Welcome to reality

Ever since I started working in IT Security more than 10 years ago, I wondered, what helps defend against malware the best?

This simple question does not stand on its own, as there are several follow-up questions to that:

  1. How is malware defined? Are we focusing solely on Viruses and Trojans, or do we also include Adware and others?
  2. What malware types are currently spread across the globe? What died of old age and what is brand new?
  3. How does malware operate? Is file-less malware a short-lived trend or is it here to stay?
  4. What needs to be done to adequately defend against malware? What capabilities are needed?
  5. What defenses are already in place? Are they configured correctly?

This blog will guide you through my research and thought process around these questions and how you can enable yourself to answer these for your own organization!

A quick glance into the past

As mentioned above, the central question “what helps best?” has followed me throughout the years, but my methods to be able to answer this question have evolved. The first interaction I had with IT Security was more than 10 years ago, where I had to manually deploy new Anti-Virus software from a USB-key to around 100 devices. The settings were configured by a colleague in our IT-Team, and my job was to help remove infections when they came up, usually by going through the various folders or registry keys and cleaning up the remains. The most common malware was Adware, and the good-ol obnoxious hotbars which were added to the browser. I remember one colleague calling into IT saying “my internet has become so small, I can barely even read 5 lines of text” which we later translated into “I had 6 hotbars installed on my Internet Explorer so there was nearly no space left for the content to be displayed”.

Exemplary picture of the “internet” getting smaller.

Jump ahead a couple of years, I started working with McAfee ePolicy Orchestrator to manage and deploy Anti-Malware from a central place automatically, and not just for our own IT, but I was was allowed to implement McAfee ePO into our customers’ environments. This greatly expanded my view into what happens in the world of malware and I started using the central reporting tool to figure out where all these threats were coming from:

 

Also, I was able to understand how the different McAfee tools helped me in detecting and blocking these threats:

But this only showed the viewpoint of one customer and I had to manually overlay them to figure out what defense mechanism worked best. Additionally, I couldn’t see what was missed by the defense mechanisms, either due to configuration, missing signatures, or disabled modules. So, these reports gave me a good viewpoint into the customers I managed, but not the complete picture. I needed a different perspective, perhaps from other customers, other tools, or even other geo-locations.

Let us jump further ahead in my personal IT security timeline to about June 2020:

How a new McAfee solution changed my perception, all while becoming a constant pun

As you could see above, I spent quite a lot of time optimizing setups and configurations to assist customers in increasing their endpoint security. As time progressed, it became clear that solely using Endpoint Protection, especially only based on signatures, was not state of the art. Protection needs to be a combination of security controls rather than the obnoxious silver bullet that is well overplayed in cybersecurity. And still, the best product or solution set doesn’t help if you don’t know what you are looking for (Question 1&2), how to prepare (Question 4) or if you misconfigured the product including all subfolders of “C:\” as an exclusion for On-Access-Scanning (Question 5).

Then McAfee released MVISION Insights this summer and it clicked in my head:

  1. I can never use the word “insights” anymore as everyone would think I use it as a pun
  2. MVISION Insights presented me with verified data of current campaigns running around in the wild
  3. MVISION Insights also aligns the description of threats to the MITRE ATT&CK® Framework, making them comparable
  4. From the ATT&CK™ Framework I could also link from the threat to defensive capabilities

With this data available it was possible to create a heatmap not just by geo-location or a very high number of new threats every day, hour or even minute, but on how specific types of campaigns are operating out in the wild. To start assessing the data, I took 60 ransomware campaigns dating between January and June 2020 and pulled out all the MITRE ATT&CK© techniques that have been used and displayed them on a heatmap:

Amber/Orange: Being used the most, green: only used in 1 or 2 campaigns

Reality Check 1: Does this mapping look accurate?

For me it does, and here is why:

  1. Initial Access comes from either having already access to a system or by sending out spear phishing attachments
  2. Execution uses various techniques from CLI, to PowerShell and WMI
  3. Files and network shares are being discovered so the ransomware knows what to encrypt
  4. Command and control techniques need to be in place to communicate with the ransomware service provider
  5. Files are encrypted on impact, which is kind of a no-brainer, but on the other hand very sound-proof on what we feel what ransomware is doing, and it is underlined by the work of the threat researchers and the resulting data

Next, we need to understand what can be done to detect and ideally block ransomware in its tracks. For this I summarized key malware defense capabilities and mapped them to the tactics being used most:

MITRE Tactic Security Capability Example McAfee solution features
Execution Attack surface reduction ENS Access Protection and Exploit Prevention, MVISION Insights recommendations
Multi-layered detection ENS Exploit Prevention, MVISION Insights telemetry, MVISION EDR Tracing, ATD file analysis
Multi-layered protection ENS On-Access-Scanning using Signatures, GTI, Machine-Learning and more
Rule & Risk-based analytics MVISION EDR tracing
Containment ENS Dynamic Application Containment
Persistence Attack surface reduction ENS Access Protection or Exploit Prevention, MVISION Insights recommendations
Multi-layered detection ENS Exploit Prevention, MVISION Insights telemetry, MVISION EDR Tracing, ATD file analysis
Sandboxing and threat analysis ATD file analysis
Rule & Risk-based analytics MVISION EDR tracing
Containment ENS Dynamic Application Containment
Defense Evasion Attack surface reduction ENS Access Protection and Exploit Prevention, MVISION Insights recommendations
Multi-layered detection ENS Exploit Prevention, MVISION Insights telemetry, MVISION EDR Tracing, ATD file analysis
Sandboxing and threat analysis ATD file analysis
Rule & Risk-based analytics MVISION EDR tracing
Containment ENS Dynamic Application Containment
Discovery Attack surface reduction ENS Access Protection and Exploit Prevention
Multi-layered detection ENS Exploit Prevention, MVISION EDR Tracing, ATD file analysis
Sandboxing and threat analysis ATD file analysis
Rule & Risk-based analytics MVISION EDR tracing
Command & Control Attack surface reduction MVISION Insights recommendations
Multi-layered detection ENS Firewall IP Reputation, MVISION Insights telemetry, MVISION EDR Tracing, ATD file analysis
Multi-layered protection ENS Firewall
Rule & Risk-based analytics MVISION EDR tracing
Containment ENS Firewall and Dynamic Application Containment
Impact Multi-layered detection MVISION EDR tracing, ATD file analysis
Rule & Risk-based analytics MVISION EDR tracing
Containment ENS Dynamic Application Containment
Advanced remediation ENS Advanced Rollback

A description of the McAfee Solutions is provided below. 

Now this allowed me to map the solutions from the McAfee portfolio to each capability, and with that indirectly to the MITRE tactics. But I did not want to end here, as different tools might take a different role in the defensive architecture. For example, MVISION Insights can give you details around your current configuration and automatically overlays it with the current threat campaigns in the wild, giving you the ability to proactively prepare and harden your systems. Another example would be using McAfee Endpoint Security (ENS) to block all unsigned PowerShell scripts, effectively reducing the risk of being hit by a file-less malware based on this technology to nearly 0%. On the other end of the scale, solutions like MVISION EDR will give you great visibility of actions that have occurred, but this happens after the fact, so there is a high chance that you will have some cleaning up to do. This brings me to the topic of “improving protection before moving into detection” but this is for another blog post.

Coming back to the mapping shown above, let us quickly do…

Reality Check 2: Does this mapping feel accurate too?

For me it does, and here is why:

  1. Execution, persistence, and defense evasion are tactics where a lot of capabilities are present, because we have a lot of mature security controls to control what is being executed, in what context and especially defense evasion techniques are good to detect and protect against.
  2. Discovery has no real protection capability mapped to it, as tools might give you indicators that something suspicious is happening but blocking every potential file discovery activity will have a very huge operational impact. However, you can use sandboxing or other techniques to assess what the ransomware is doing and use the result from this analysis to stop ongoing malicious processes.
  3. Impact has a similar story, as you cannot block any process that encrypts a file, as there are many legitimate reasons to do so and hundreds of ways to accomplish this task. But again, you can monitor these actions well and with the right technology in place, even roll back the damage that has been done.

Now with all this data at hand we can come to the final step and bring it all together in one simple graph.

One graph to bind them…

Before we jump into our conclusion, here is a quick summary of the actions I have taken:

  1. Gather data from 60 ransomware campaigns
  2. Pull out the MITRE ATT&CK techniques being used
  3. Map the necessary security capabilities to these techniques
  4. Bucketize the capabilities depending on where they are in the threat defense lifecycle
  5. Map McAfee solutions to the capabilities and applying a weight to the score
  6. Calculate the score for each solution
  7. Create graph for the ransomware detection & protection score for our most common endpoint bundles and design the best fitting security architecture

So, without further ado and with a short drumroll I want to present to you the McAfee security architecture that best defends against current malware campaigns:

For reference, here is a quick breakdown of the components that make up the architecture above:

MVISION ePO is the SaaS-based version of our famous security management solution, which makes it possible to manage a heterogenous set of systems, policies, and events from a central place. Even though I have mentioned the SaaS-based version here, the same is true for our ePO on-premises software as well.

MVISION Insights is a key data source that helps organizations understand what campaigns and threats are trending. This is based on research from our Advanced Threat Research (ATR) team who use our telemetry data inside our Global Threat Intelligence (GTI) big-data platform to enhance the details that are provided.

MVISION Endpoint Detect & Response (EDR) is present in multiple boxes here, as it is a sensor on one side, which sits on the endpoint and collects data, and it is also a cloud service which receives, stores and analyses the data.

EPP is our Endpoint Protection Platform, which contains multiple items working in conjunction. First there is McAfee Endpoint Security (ENS) that is sitting on the device itself and has multiple detection and protection capabilities. For me, the McAfee Threat Intelligence Exchange (TIE) server is always a critical piece to McAfee’s Endpoint Protection Platform and has evolved from a standalone feature to an integrated building block inside ePO and is therefore not shown in the graphic above.

McAfee Advanced Threat Defense (ATD) extends the capabilities of both EPP and EDR, as it can run suspicious files in a separated environment and shares the information gathered with the other components of the McAfee architecture and even 3rd-party tools. It also goes the other way around as ATD allows other security controls to forward files for analysis in our sandbox, but this might be a topic for another blog post.

All the items listed above can be acquired by licensing our MVISION Premium suite in combination with McAfee ATD.

Based on the components and the mapping to the capabilities, I was also able to create a graph based on our most common device security bundles and their respective malware defense score:

In the graph above you can see four of our most sold bundles, ranging from the basic MVISION Standard, up to MVISION Premium in combination with McAfee Advanced Threat Defense (ATD). The line shows the ransomware detection & protection score, steadily rising as you go from left to right. Interestingly, the cost per point, i.e. how much dollar you need to spend to get one point, is much lower when buying the largest option in comparison to the smaller ones. As the absolute cost varies on too many variables, I have omitted an example here. Contact your local sales representative to gather an estimated calculation for your environment.

So, have I come to this conclusion by accident? Let us find out in the last installment of the reality check:

Reality Check 3:  Is this security architecture well suited for today’s threats?

For me it does, and here is why:

  1. It all starts with the technology on the endpoint. A good Endpoint Protection Platform can not only prevent attacks and harden the system, but it can also protect against threats when they are written on a disk or are executed, and then start malicious activities. But what is commonly overlooked: A good endpoint solution can also bring in a lot of visibility, making it the foundation of every good incident response practice.
  2. ATD plays a huge role in the overall architecture as you can see from the increase in points between MVISION Premium and MVISION Premium + ATD in the graph above. It allows the endpoint to have another opinion, which is not limited in time and resources to come to a conclusion, and it has no scan exceptions applied when checking a file. As this is integrated into the protection, it helps block threats before spreading and it certainly provides tremendous details around the malware that was discovered.
  3. MVISION Insights also plays a huge role in both preventative actions, so that you can harden your machines before you are hit, but also in detecting things that might have slipped through the cracks or where new indicators have emerged only after a certain time period.
  4. MVISION EDR has less impact on the scoring, as it is a pure detection technology. However, it also has a similar advantage as our McAfee ATD, as the client only forwards the data, and the heavy lifting is done somewhere else. It also goes back around, as EDR can pull in data from other tools shown above, like ENS, TIE or ATD just to name a few.
  5. MVISION ePO must be present in any McAfee architecture, as it is the heart and soul for every operational task. From managing policies, rollouts, client-tasks, reporting and much more, it plays a critical role and has for more than two decades now.

And the answer is not 42

While writing up my thoughts into the blog post, I was reminded of the “Hitchhikers Guide to the Galaxy”, as my journey in cybersecurity started out with the search for the answer to everything. But over the years it evolved into the multiple questions I prompted at the start of the article:

  1. How is malware defined? Are we focusing solely on Viruses and Trojans, or do we also include Adware and others?
  2. What malware types are currently spread across the globe? What died of old age and what is brand new?
  3. How does malware operate? Is file-less malware a short-lived trend or is it here to stay?
  4. What needs to be done to adequately defend against malware? What capabilities are needed?
  5. What defenses are already in place? Are they configured correctly?

And certainly, the answers to these questions are a moving target. Not only do the tools and techniques by the adversaries evolve, so do all the capabilities on the defensive side.

I welcome you to take the information provided by my research and apply it to your own security architecture:

  • Do you have the right capabilities to protect against the techniques used by current ransomware campaigns?
  • Is detection already a key part of your environment and how does it help to improve your protection?
  • Have you recently tested your defenses against a common threat campaign?
  • Are you sharing detections within your architecture from one security tool to the other?
  • What score would your environment reach?

Thank you for reading this blog post and following my train of thought. I would love to hear back from you, on how you assess yourself, what could be the next focus area for my research or if you want to apply the scoring mechanism on your environment! So please find me on LinkedIn or Twitter, write me a short message or just say “Hi!”.

I also must send out a big “THANK YOU!” to all my colleagues at McAfee helping out during my research: Mo Cashman, Christian Heinrichs, John Fokker, Arnab Roy, James Halls and all the others!

 

The post McAfee Defenders Blog: Reality Check for your Defenses appeared first on McAfee Blogs.