VDB-101241 · CVE-2017-8929 · Qualys 276739

YARA 3.5.0 Rule libyara/sizedstr.c sized_string_cmp use after free

CVSS Meta Temp Score
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CTI Interest Score
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A vulnerability classified as critical has been found in YARA 3.5.0. This affects the function sized_string_cmp of the file libyara/sizedstr.c of the component Rule Handler. The manipulation with an unknown input leads to a use after free vulnerability. CWE is classifying the issue as CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

The sized_string_cmp function in libyara/sizedstr.c in YARA 3.5.0 allows remote attackers to cause a denial of service (use-after-free and application crash) via a crafted rule.

The bug was discovered 05/12/2017. The weakness was released 05/14/2017 (GitHub Repository). The advisory is shared at github.com. This vulnerability is uniquely identified as CVE-2017-8929 since 05/14/2017. 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 2 days. During that time the estimated underground price was around $0-$5k. The vulnerability scanner Nessus provides a plugin with the ID 100971 (Fedora 24 : yara (2017-5c55ef46ee)), which helps to determine the existence of the flaw in a target environment. It is assigned to the family Fedora Local Security Checks and running in the context l. The commercial vulnerability scanner Qualys is able to test this issue with plugin 276739 (Fedora Security Update for yara (FEDORA-2017-5c55ef46ee)).

Upgrading 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 (100971). Entry connected to this vulnerability is available at VDB-99229.





CPE 2.3info

CPE 2.2info


VulDB CVSS-B Score: 🔍
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VulDB Meta Base Score: 7.4
VulDB Meta Temp Score: 6.9

VulDB Base Score: 7.3
VulDB Temp Score: 6.4
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NVD Base Score: 7.5
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Class: Use after free
CWE: CWE-416 / CWE-119

Local: No
Remote: Yes

Availability: 🔍
Status: Not defined

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Nessus ID: 100971
Nessus Name: Fedora 24 : yara (2017-5c55ef46ee)
Nessus File: 🔍
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OpenVAS ID: 867773
OpenVAS Name: Fedora Update for yara FEDORA-2017-926e11c76e
OpenVAS File: 🔍
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Threat Intelligenceinfo

Interest: 🔍
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Recommended: Upgrade
Status: 🔍

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Patch: github.com


05/12/2017 🔍
05/14/2017 +2 days 🔍
05/14/2017 +0 days 🔍
05/14/2017 +0 days 🔍
05/16/2017 +2 days 🔍
06/17/2017 +32 days 🔍
06/22/2017 +5 days 🔍
12/06/2022 +1993 days 🔍


Advisory: FEDORA-2017-5c55ef46ee
Status: Not defined
Confirmation: 🔍

CVE: CVE-2017-8929 (🔍)
OSVDB: - CVE-2017-8929 - YARA - Use-After-Free Issue

See also: 🔍


Created: 05/16/2017 03:57 AM
Updated: 12/06/2022 01:52 PM
Changes: 05/16/2017 03:57 AM (74), 09/26/2020 05:41 PM (5), 12/06/2022 01:47 PM (5), 12/06/2022 01:52 PM (1)
Complete: 🔍
Cache ID: 34:1BB:40


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