unrar up to 5.5.6 libunrar.a Unpack::Unpack20 out-of-bounds

Summaryinfo

A vulnerability has been found in unrar up to 5.5.6 and classified as critical. This affects the function Unpack::Unpack20 of the file libunrar.a. Performing a manipulation results in out-of-bounds. This vulnerability is known as CVE-2017-12941. Remote exploitation of the attack is possible. No exploit is available. The affected component should be upgraded.

Detailsinfo

A vulnerability, which was classified as critical, was found in unrar up to 5.5.6. This affects the function Unpack::Unpack20 of the file libunrar.a. The manipulation with an unknown input leads to a out-of-bounds vulnerability. CWE is classifying the issue as CWE-125. The product reads data past the end, or before the beginning, of the intended buffer. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

libunrar.a in UnRAR before 5.5.7 has an out-of-bounds read in the Unpack::Unpack20 function.

The bug was discovered 08/15/2017. The weakness was published 08/18/2017 as not defined mailinglist post (oss-sec). The advisory is shared at seclists.org. This vulnerability is uniquely identified as CVE-2017-12941 since 08/18/2017. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. Technical details are known, but no exploit is available.

The vulnerability was handled as a non-public zero-day exploit for at least 3 days. During that time the estimated underground price was around $0-$5k. The vulnerability scanner Nessus provides a plugin with the ID 103463 (GLSA-201709-24 : RAR, UnRAR: Multiple vulnerabilities), which helps to determine the existence of the flaw in a target environment. It is assigned to the family Gentoo Local Security Checks and running in the context l. The commercial vulnerability scanner Qualys is able to test this issue with plugin 171008 (SUSE Enterprise Linux Security Update for unrar (SUSE-SU-2018:0862-1)).

Upgrading to version 5.5.7 eliminates this vulnerability. A possible mitigation has been published 2 months after the disclosure of the vulnerability.

The vulnerability is also documented in the vulnerability database at Tenable (103463). Similar entries are available at VDB-105462, VDB-105464, VDB-105466 and VDB-119570. Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Affected

• McAfee Web Gateway 7.8.1.0 up to 7.8.1.5

Productinfo

Name

• unrar

Version

• 5.5.0
• 5.5.1
• 5.5.2
• 5.5.3
• 5.5.4
• 5.5.5
• 5.5.6

CPE 2.3info

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CPE 2.2info

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Entryinfo

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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