Archive for March, 2014


New Microsoft Word Zero-Day Used in Targeted Attacks

Microsoft warned on Monday of a remote code execution vulnerability (CVE-2014-1761) in Microsoft Word that is being actively exploited in 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 email message in Microsoft Outlook while using Microsoft Word as the email viewer,” Microsoft explained in the advisory.

If successfully exploited, an attacker could gain the same user rights as the current user, Microsoft said, noting that users whose accounts are configured to have fewer user rights on the system could be less impacted than accounts with administrative privileges.

Applying the Microsoft Fix it solution, “Disable opening RTF content in Microsoft Word,” prevents the exploitation of this issue through Microsoft Word, Microsoft said.

Specifically, the issue is caused when Microsoft Word parses specially crafted RTF-formatted data causing system memory to become corrupted, giving a potential attacker the ability execute arbitrary code on the affected system.

“In a web-based attack scenario, an attacker could host a website that contains a webpage that contains a specially crafted RTF file that is used to attempt to exploit this vulnerability, Microsoft explained. “In addition, compromised websites and websites that accept or host user-provided content or advertisements could contain specially crafted content that could exploit this vulnerability. In all cases, however, an attacker would have no way to force users to visit these websites. Instead, an attacker would have to convince users to visit the website, typically by getting them to click a link in an email message or Instant Messenger message that takes users to the attacker’s website.”

The vulnerability could be exploited through Microsoft Outlook only when using Microsoft Word as the email viewer, Microsoft warned. By default, Word is the email reader in Microsoft Outlook 2007, Microsoft Outlook 2010, and Microsoft Outlook 2013.

Microsoft did not share any details on the attacks that leveraged the vulnerability, but did credit Drew Hintz, Shane Huntley, and Matty Pellegrino of the Google Security Team for reporting it to Microsoft.

 Source: Security Week

Android 4.4.3 KitKat update reportedly coming soon

After a never-before-seen version of KitKat has been spotted a few days ago – version KTU65 – suggesting that Google may release at least one more KitKat update before moving to a new Android OS version, a new tweet from known developer LlabTooFeR says that Android 4.4.3 may be just around the corner, with version KTU72B identified as the upcoming software update.

“Android 4.4.3 is under testing. Build number is KTU72B,” the developer wrote. “Probably it will fix known camera bug.” This KitKat version’s code name suggests this build (dated March 13) is newer than the previous one (dated March 6,) although the developer did not share any details as to when Google will actually release it.

Similarly, it’s not clear whether the update will bring any new features, on top of the expected camera fix for the Nexus 5, and whether it will be available to other devices as well. Still, this appears to be first time these newly discovered KitKat builds are associated with “Android 4.4.3.”

The latest KitKat software version available to Android users is KOT49H (Android 4.4.2), although only some devices have been updated so far, including Nexus tablets and smartphones. A recent report said that Google will unveil Android 4.5 this summer, likely together with new Nexus devices – the company is rumored to ship at least one new tablet this year, with rumors indicating that a Nexus device with an 8.9-inch may be in the works.

Source: BGR

Critical crypto bug leaves Linux, hundreds of apps open to eavesdropping

Hundreds of open source packages, including the Red Hat, Ubuntu, and Debian distributions of Linux, are susceptible to attacks that circumvent the most widely used technology to prevent eavesdropping on the Internet, thanks to an extremely critical vulnerability in a widely used cryptographic code library.

The bug in the GnuTLS library makes it trivial for attackers to bypass secure sockets layer (SSL) and Transport Layer Security (TLS) protections available on websites that depend on the open source package. Initial estimates included in Internet discussions such as this one indicate that more than 200 different operating systems or applications rely on GnuTLS to implement crucial SSL and TLS operations, but it wouldn’t be surprising if the actual number is much higher. Web applications, e-mail programs, and other code that use the library are vulnerable to exploits that allow attackers monitoring connections to silently decode encrypted traffic passing between end users and servers.

The bug is the result of commands in a section of the GnuTLS code that verify the authenticity of TLS certificates, which are often known simply as X509 certificates. The coding error, which may have been present in the code since 2005, causes critical verification checks to be terminated, drawing ironic parallels to the extremely critical “goto fail” flaw that for months put users of Apple’s iOS and OS X operating systems at risk of surreptitious eavesdropping attacks. Apple developers have since patched the bug.

“It was discovered that GnuTLS did not correctly handle certain errors that could occur during the verification of an X.509 certificate, causing it to incorrectly report a successful verification,” an advisory issued by Red Hat warned. “An attacker could use this flaw to create a specially crafted certificate that could be accepted by GnuTLS as valid for a site chosen by the attacker.”

GnuTLS developers published this bare-bones advisory that urges all users to upgrade to version 3.2.12. The flaw, formally indexed as CVE-2014-0092, is described by a GnuTLS developer as “an important (and at the same time embarrassing) bug discovered during an audit for Red Hat.” Debian’s advisory is here.

As was the case with last week’s critical encryption bug from Apple, the GnuTLS vulnerability is the result of someone making mistakes in source code that controls critical functions of the program. This time, instead of a single misplaced “goto fail” command, the mistakes involve errors with several “goto cleanup” calls. The GnuTLS program, in turn, prematurely terminates code sections that are supposed to establish secure TLS connections only after the other side presents a valid X509 certificate signed by a trusted source. Attackers can exploit the error by presenting vulnerable systems with a fraudulent certificate that is never rejected, despite its failure to pass routine security checks. The failure may allow attackers using a self-signed certificate to pose as the cryptographically authenticated operator of a vulnerable website and to decrypt protected communications. It’s significant that no one managed to notice such glaring errors, particularly since they were contained in code that anyone can review.

Security researchers are still studying the vulnerability and assessing its effect on the wide array of OSes and applications that depend on GnuTLS. For the moment, readers should assume that the severity is critical given the dizzying amount of downstream code that may be affected. One example: the apt-get installer some distributions of Linux use to distribute and update applications relies on GnuTLS, although exploits against the package can probably be caught by cryptographic code-signing of the downloaded program (thanks to readers for pointing out this secondary level of protection). Version 3 of lib-curl, which is distributed in Debian and Ubuntu, also depends on GnuTLS. Some Debian- and Ubuntu-based virtual private networking applications that work with Cisco Systems hardware are also affected. This list goes on and on.

Source: ArsTechnica