VDB-99244 · CVE-2017-5923 · BID 98080

YARA 3.5.0 libyara/grammar.y yara_yyparse out-of-bounds

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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A vulnerability classified as problematic was found in YARA 3.5.0. This vulnerability affects the function yara_yyparse of the file libyara/grammar.y. The manipulation with an unknown input leads to a out-of-bounds vulnerability. The CWE definition for the vulnerability is CWE-125. The software reads data past the end, or before the beginning, of the intended buffer. As an impact it is known to affect availability.

The bug was discovered 01/23/2017. The weakness was shared 04/03/2017 (GitHub Repository). The advisory is shared for download at github.com. This vulnerability was named CVE-2017-5923 since 02/07/2017. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. There are known technical details, but no exploit is available.

The vulnerability was handled as a non-public zero-day exploit for at least 70 days. During that time the estimated underground price was around $0-$5k. The vulnerability scanner Nessus provides a plugin with the ID 99743 (Fedora 25 : yara (2017-11ac1e31eb)), 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 local. The commercial vulnerability scanner Qualys is able to test this issue with plugin 276651 (Fedora Security Update for yara (FEDORA-2017-11ac1e31eb)).

Upgrading eliminates this vulnerability. A possible mitigation has been published 4 weeks after the disclosure of the vulnerability.

The vulnerability is also documented in the vulnerability database at Tenable (99743). The entries 99229, 99230, 99245 and 100634 are related to this item.



CPE 2.3info

CPE 2.2info


VulDB Meta Base Score: 6.4
VulDB Meta Temp Score: 6.1

VulDB Base Score: 5.3
VulDB Temp Score: 4.7
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 7.5
NVD Vector: 🔍



VulDB Base Score: 🔍
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NVD Base Score: 🔍


Class: Out-of-bounds
CWE: CWE-125 / CWE-119
ATT&CK: Unknown

Local: No
Remote: Yes

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍


Nessus ID: 99743
Nessus Name: Fedora 25 : yara (2017-11ac1e31eb)
Nessus File: 🔍
Nessus Risk: 🔍
Nessus Family: 🔍
Nessus Context: 🔍

OpenVAS ID: 867773
OpenVAS Name: Fedora Update for yara FEDORA-2017-9941306740
OpenVAS File: 🔍
OpenVAS Family: 🔍

Qualys ID: 🔍
Qualys Name: 🔍

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍


Recommended: Upgrade
Status: 🔍

Reaction Time: 🔍
0-Day Time: 🔍
Exposure Time: 🔍

Patch: github.com


01/23/2017 🔍
02/07/2017 +15 days 🔍
04/03/2017 +55 days 🔍
04/03/2017 +0 days 🔍
04/03/2017 +0 days 🔍
04/10/2017 +7 days 🔍
04/29/2017 +19 days 🔍
05/01/2017 +2 days 🔍
11/24/2022 +2033 days 🔍


Advisory: FEDORA-2017-11ac1e31eb
Status: Not defined
Confirmation: 🔍

CVE: CVE-2017-5923 (🔍)
SecurityFocus: 98080 - YARA 'yara_yyparse()' Function Denial of Service Vulnerability
OSVDB: - CVE-2017-5923 - YARA - Out-of-Bounds Read Issue

See also: 🔍


Created: 04/03/2017 04:57 PM
Updated: 11/24/2022 05:57 PM
Changes: 04/03/2017 04:57 PM (81), 11/24/2022 05:50 PM (5), 11/24/2022 05:57 PM (1)
Complete: 🔍


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