GNU C Library wordexp WRDE_NOCMD input validation

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.
5.3$0-$5k0.00

Summaryinfo

A vulnerability was found in GNU C Library and classified as problematic. Affected is the function wordexp. Executing a manipulation of the argument WRDE_NOCMD can lead to input validation. The identification of this vulnerability is CVE-2014-7817. Furthermore, there is an exploit available. It is best practice to apply a patch to resolve this issue.

Detailsinfo

A vulnerability was found in GNU C Library (Software Library) (the affected version is unknown). It has been declared as problematic. This vulnerability affects the function wordexp. The manipulation of the argument WRDE_NOCMD with an unknown input leads to a input validation vulnerability. The CWE definition for the vulnerability is CWE-20. The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

The wordexp function in GNU C Library (aka glibc) 2.21 does not enforce the WRDE_NOCMD flag, which allows context-dependent attackers to execute arbitrary commands, as demonstrated by input containing "$((`...`))".

The weakness was shared 11/20/2014 by Tim Waug as confirmed bug report (Bugzilla). The advisory is available at sourceware.org. This vulnerability was named CVE-2014-7817 since 10/03/2014. The exploitation appears to be easy. Local access is required to approach this attack. No form of authentication is required for a successful exploitation. Technical details and also a public exploit are known.

A public exploit has been developed by Vasyl Kaigorodov in ANSI C and been published before and not just after the advisory. It is possible to download the exploit at bugzilla.redhat.com. It is declared as proof-of-concept. The vulnerability was handled as a non-public zero-day exploit for at least 24 days. During that time the estimated underground price was around $0-$5k. The vulnerability scanner Nessus provides a plugin with the ID 80114 (Oracle Linux 7 : glibc (ELSA-2014-2023)), which helps to determine the existence of the flaw in a target environment. It is assigned to the family Oracle Linux Local Security Checks. The commercial vulnerability scanner Qualys is able to test this issue with plugin 195694 (Ubuntu Security Notification for Eglibc, Glibc Vulnerabilities (USN-2432-1)). The code used by the exploit is:

#include <wordexp.h>
int main (void)
{
  wordexp_t we;
  return wordexp ("$((1`touch /tmp/x`))", &we, WRDE_NOCMD);
}

Applying a patch is able to eliminate this problem. The bugfix is ready for download at sourceware.org.

The vulnerability is also documented in the databases at X-Force (98852), Tenable (80114), SecurityFocus (BID 71216†), Secunia (SA62100†) and Vulnerability Center (SBV-47448†). Additional details are provided at bugzilla.redhat.com. The entries VDB-68352, VDB-73110 and VDB-74936 are related to this item. Once again VulDB remains the best source for vulnerability data.

Productinfo

Type

Vendor

Name

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.9
VulDB Meta Temp Score: 5.3

VulDB Base Score: 5.9
VulDB Temp Score: 5.3
VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
💳💳💳💳💳💳
💳💳💳💳💳💳
💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
UnlockUnlockUnlockUnlockUnlockUnlock
UnlockUnlockUnlockUnlockUnlockUnlock
UnlockUnlockUnlockUnlockUnlockUnlock

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

NVD Base Score: 🔍

Exploitinginfo

Class: Input validation
CWE: CWE-20
CAPEC: 🔍
ATT&CK: 🔍

Physical: Partially
Local: Yes
Remote: No

Availability: 🔍
Access: Public
Status: Proof-of-Concept
Author: Vasyl Kaigorodov
Programming Language: 🔍
Download: 🔍

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

0-DayUnlockUnlockUnlockUnlock
TodayUnlockUnlockUnlockUnlock

Nessus ID: 80114
Nessus Name: Oracle Linux 7 : glibc (ELSA-2014-2023)
Nessus File: 🔍
Nessus Risk: 🔍
Nessus Family: 🔍
Nessus Port: 🔍

OpenVAS ID: 14611
OpenVAS Name: Amazon Linux Local Check: ALAS-2015-468
OpenVAS File: 🔍
OpenVAS Family: 🔍

Qualys ID: 🔍
Qualys Name: 🔍

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Patch
Status: 🔍

0-Day Time: 🔍

Patch: a39208bd7fb76c1b01c127b4c61f9bfd915bfe7c

Timelineinfo

10/03/2014 🔍
10/27/2014 +24 days 🔍
11/20/2014 +24 days 🔍
11/20/2014 +0 days 🔍
11/20/2014 +0 days 🔍
11/21/2014 +1 days 🔍
11/24/2014 +3 days 🔍
12/08/2014 +14 days 🔍
12/19/2014 +11 days 🔍
01/08/2015 +20 days 🔍
02/25/2022 +2605 days 🔍

Sourcesinfo

Vendor: gnu.org

Advisory: RHSA-2014:2023
Researcher: Tim Waug
Status: Confirmed
Confirmation: 🔍

CVE: CVE-2014-7817 (🔍)
GCVE (CVE): GCVE-0-2014-7817
GCVE (VulDB): GCVE-100-68254

OVAL: 🔍

X-Force: 98852 - GNU C Library wordexp() command execution, Medium Risk
SecurityFocus: 71216 - GNU glibc CVE-2014-7817 Arbitrary Command Execution Vulnerability
Secunia: 62100 - Red Hat update for glibc, Moderately Critical
Vulnerability Center: 47448 - GNU glibc 2.21 Local Code Execution due to a Flaw in Wordexp Function, Medium

scip Labs: https://www.scip.ch/en/?labs.20161013
Misc.: 🔍
See also: 🔍

Entryinfo

Created: 11/21/2014 09:28
Updated: 02/25/2022 07:31
Changes: 11/21/2014 09:28 (86), 06/13/2017 09:18 (7), 02/25/2022 07:20 (4), 02/25/2022 07:26 (1), 02/25/2022 07:31 (2)
Complete: 🔍
Cache ID: 216:A8D:103

Discussion

No comments yet. Languages: en.

Please log in to comment.

◂ PreviousOverviewNext ▸

Are you interested in using VulDB?

Download the whitepaper to learn more about our service!