Monthly Archives: May 2016

Avast

Avast Software Updater can help protect you from security loopholes, like the recent 7 Zip vulnerabilities

Last week, Talos discovered multiple vulnerabilities in 7-Zip, a popular, open source file archiver. The vulnerabilities are particularly severe as many products, including antivirus software, implement 7-Zip in their software. When vulnerabilities are found, it is the responsibility of software owners to patch them. However, these patches are useless, unless users update their software.

Avast is not affected by these vulnerabilities, but if you are a non-Avast user we recommend you update your antivirus software, if you haven’t done so already.

About the vulnerabilities

The two vulnerabilities found are CVE-2016-2335 and CVE-2016-2334. The first vulnerability is an out-of-bounds read vulnerability, which exists due to how 7-Zip handles Universal Disk Format (UDF) files and could allow attackers to remotely execute code.

The second vulnerability is an exploitable heap overflow vulnerability, found in the Archive::NHfs::CHandler::ExtractZlibFile method functionality. In the HFS+ file system, files, depending on their size, can be split into blocks. There is no check to see if the size of the block is bigger than size of the buffer, which can result in a malformed block size which exceeds the buffer size. This will cause a buffer overflow and heap corruption.

What you should do

As mentioned above, it is up to software publishers to provide their users with vulnerability fixes, but these are futile if users don’t take action and update their software. It is vital that you frequently update all software, including your operating system, on a regular basis.

Security

Ubuntu Security Notice USN-2960-1

Ubuntu Security Notice 2960-1 – An out of bounds write was discovered in Blink. If a user were tricked in to opening a specially crafted website, an attacker could potentially exploit this to cause a denial of service via renderer crash, or execute arbitrary code. It was discovered that Blink assumes that a frame which passes same-origin checks is local in some cases. If a user were tricked in to opening a specially crafted website, an attacker could potentially exploit this to cause a denial of service via renderer crash, or execute arbitrary code. Various other issues were also addressed.

Security

Ubuntu Security Notice USN-2973-1

Ubuntu Security Notice 2973-1 – Christian Holler, Tyson Smith, and Phil Ringalda discovered multiple memory safety issues in Thunderbird. If a user were tricked in to opening a specially crafted message, an attacker could potentially exploit these to cause a denial of service via application crash, or execute arbitrary code. Hanno Boeck discovered that calculations with mp_div and mp_exptmod in NSS produce incorrect results in some circumstances, resulting in cryptographic weaknesses. Various other issues were also addressed.