Category: Office

Oct 11 2017

Krebs on Security 2017-10-11 10:18:40

Microsoft on Tuesday released software updates to fix at least 62 security vulnerabilities in Windows, Office and other software. Two of those flaws were detailed publicly before yesterday’s patches were released, and one of them is already being exploited in active attacks, so attackers already have a head start.

brokenwindowsRoughly half of the flaws Microsoft addressed this week are in the code that makes up various versions of Windows, and 28 of them were labeled “critical” — meaning malware or malicious attackers could use the weaknesses to break into Windows computers remotely with no help from users.

One of the publicly disclosed Windows flaws (CVE-2017-8703) fixed in this batch is a problem with a feature only present in Windows 10 known as the Windows Subsystem for Linux, which allows Windows 10 users to run unmodified Linux binary files. Researchers at CheckPoint recently released some interesting research worth reading about how attackers might soon use this capability to bypass antivirus and other security solutions on Windows.

The bug quashed this week that’s being actively exploited resides in Microsoft Office (CVE-2017-11826), and Redmond says attackers could seize control over a vulnerable system just by convincing someone to open a booby-trapped Word file. Another Office vulnerability, (CVE-2017-11776), involves a flaw in Outlook’s ability to encrypt messages; SEC-Consult has more details on this bug.

Another critical flaw (CVE-2017-11779) addresses a scary vulnerability in the domain name system (DNS) component of Windows 8 and Windows Server 2012. According to research from Bishop Fox, the security firm credited with finding and reporting the bug, this flaw could be exploited quite easily to gain complete control over vulnerable systems if the attacker controls or compromises a local network (think Wi-Fi hotspot).

Normally, Adobe uses Microsoft’s Patch Tuesday (the second Tuesday of each month) to release its own fixes for Flash Player, Reader and other products. However, this time around the company has no security updates available. Adobe did release a new version of Flash that includes bug fixes (v. 27.0.0.159), but generally speaking only even-numbered Flash releases include security fixes.

For additional commentary on October’s bundle of updates from Microsoft, see these blogs from security vendors Ivanti and Qualys. For those looking for a straight-up list of which patches deserve priority, check out the always useful roundup from the SANS Internet Storm Center.

May 09 2017

Microsoft’s recent success in blocking in-the-wild attacks is eerily good

Enlarge (credit: Stephen Brashear / Getty Images News)

Microsoft engineers have neutralized a series of attacks that took control of targeted computers by exploiting independent vulnerabilities in Word and Windows. Remarkably, the software maker said fixes or partial mitigations for all four security bugs were released before it received private reports of the attacks.

Both versions of the attacks used malformed Word documents that were attached to phishing e-mails sent to a highly select group of targets. The malicious documents chained together two exploits, one that targeted flaws in an Encapsulated PostScript filter in Word and the other that targeted elevation-of-privilege bugs in Windows so that the attack could break out of the security sandbox that fortifies Office. Encapsulated PostScript is an old format that's rarely used any more.

One version of the attacks combined an exploit for a Word EPS flaw designated as CVE-2017-0261 with an exploit for CVE-2017-0001, a Windows privilege-escalation bug. By the time Microsoft received a private report of ongoing attacks in March, the company had already released a partial fix as part of its March Update Tuesday release. A second attack version exploited an EPS flaw indexed as CVE-2017-0262 in combination with CVE-2017-0263, a separate Windows privilege-elevation flaw.

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Mar 04 2016

It’s 2016, so why is the world still falling for Office macro malware?

In the late 1990s, Microsoft Office macros were a favorite vehicle for surreptitiously installing malware on the computers of unsuspecting targets. Microsoft eventually disabled the automated scripts by default, a setting that forced attackers to look for new infection methods. Remotely exploiting security bugs in Internet Explorer, Adobe Flash, and other widely used software soon came into favor.

Over the past two years, Office Macros have made a dramatic comeback that has reached almost a fevered pitch in the past few months. Booby-trapped Excel macros, for instance, were one of the means by which Ukrainian power authorities were infected in the weeks or months leading up to December's hacker-caused outage that affected 225,000 people. "Locky," a particularly aggressive strain of crypto ransomware that appeared out of nowhere two weeks ago, also relies on Word macros. The return of the macro-delivered malware seemed to begin in late 2014 with the advent of a then-new banking trojan called Dridex.

The return of the macro may have been a reaction to security improvements that Adobe, Microsoft, and Oracle have made to their software. Not only were the companies patching dangerous bugs more quickly, but in many cases, they fortified their code with defenses that caused exploits to simply crash the application rather than force it to execute malicious code. Streamlined update mechanisms and greater end user awareness about the importance of installing security patches right away may also have made code-execution exploits to fall out of favor.

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Mar 24 2014

Zero-day vulnerability in Microsoft Word under active attack

Attackers are exploiting a newly discovered vulnerability in Microsoft Word that makes it possible to remotely seize control of computers, the company warned.

The in-the-wild attacks work by creating booby-trapped documents in the Rich Text Format (RTF) that exploit a vulnerability in the 2010 version of Microsoft Word, Microsoft warned in an advisory published Monday. Similar attacks work against other versions of Word, including 2003, 2007, and 2013 for Windows, Microsoft Office for Mac 2011, and multiple versions of Microsoft SharePoint Server. E-mails that are viewed or previewed using a default setting in Outlook allow the attacker to gain the same system privileges as the user who is currently logged in.

"Microsoft is aware of a vulnerability affecting supported versions of Microsoft Word," Monday's advisory stated. "At this time, we are aware of limited, targeted attacks directed at Microsoft Word 2010. The vulnerability could allow remote code execution if a user opens a specially crafted RTF file using an affected version of Microsoft Word or previews or opens a specially crafted RTF e-mail message in Microsoft Outlook while using Microsoft Word as the e-mail viewer."

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