CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
6.1	$0-$5k	0.00

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 product reads data past the end, or before the beginning, of the intended buffer. As an impact it is known to affect availability. CVE summarizes:

libyara/grammar.y in YARA 3.5.0 allows remote attackers to cause a denial of service (heap-based out-of-bounds read and application crash) via a crafted rule that is mishandled in the yara_yyparse function.

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 l. 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).

Productinfo

Name

• YARA

Version

• 3.5.0

License

• open-source

CPE 2.3info

• 🔍
• 🔍

CPE 2.2info

• 🔍
• 🔍

CVSSv4info

VulDB CVSS-B Score: 🔍
VulDB CVSS-BT Score: 🔍
VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

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: 🔍

CVSSv2info

AV	AC	Au	C	I	A
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳

Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
unlock	unlock	unlock	unlock	unlock	unlock
unlock	unlock	unlock	unlock	unlock	unlock
unlock	unlock	unlock	unlock	unlock	unlock

VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

NVD Base Score: 🔍

Exploitinginfo

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

Local: No
Remote: Yes

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

0-Day	unlock	unlock	unlock	unlock
Today	unlock	unlock	unlock	unlock

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: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

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

Patch: github.com

Timelineinfo

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 🔍

Sourcesinfo

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

Entryinfo

Created: 04/03/2017 16:57
Updated: 11/24/2022 17:57
Changes: 04/03/2017 16:57 (81), 11/24/2022 17:50 (5), 11/24/2022 17:57 (1)
Complete: 🔍
Cache ID: 3:D04:103

Discussion

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