Todd Miller sudo up to 1.6.9/1.8.5 env.c validate_env_vars Environment Variable input validation

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5.2$0-$5k0.00

A vulnerability classified as problematic has been found in Todd Miller sudo up to 1.6.9/1.8.5 (Operating System Utility Software). Affected is the function validate_env_vars of the file env.c. The manipulation as part of a Environment Variable leads to a input validation vulnerability. CWE is classifying the issue as 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. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

Sudo 1.6.9 before 1.8.5, when env_reset is disabled, does not properly check environment variables for the env_delete restriction, which allows local users with sudo permissions to bypass intended command restrictions via a crafted environment variable.

The weakness was published 03/05/2014 by Sebastien Macke as sudo: security policy bypass when env_reset is disabled as confirmed mailinglist post (oss-sec). The advisory is available at seclists.org. This vulnerability is traded as CVE-2014-0106 since 12/03/2013. The exploitability is told to be easy. Local access is required to approach this attack. The exploitation doesn't require any form of authentication. Technical details are known, but there is no available exploit. The reason for this vulnerability is this part of code:

if (okvar == FALSE)
The advisory points out:
Due to a logic bug in the validate_env_vars() function, if the env_reset option is disabled, environment variables specified on the command line are permitted when they should not be (and vice versa). This can be used by a malicious user to run arbitrary programs by manipulating the environment of a command the user is legitimately allowed to run.

The vulnerability scanner Nessus provides a plugin with the ID 73327 (SuSE 11.3 Security Update : sudo (SAT Patch Number 9044)), which helps to determine the existence of the flaw in a target environment. It is assigned to the family SuSE Local Security Checks. The commercial vulnerability scanner Qualys is able to test this issue with plugin 123806 (Apple Mac OS X v10.10.5 and Security Update 2015-006 Not Installed (APPLE-SA-2015-08-13-2)).

Upgrading to version 1.8.5 eliminates this vulnerability. Applying a patch is able to eliminate this problem. The bugfix is ready for download at sudo.ws. It is possible to mitigate the problem by applying the configuration setting Not Disable env_reset. The best possible mitigation is suggested to be upgrading to the latest version. The vulnerability will be addressed with the following lines of code:

if (okvar == TRUE)

The vulnerability is also documented in the databases at X-Force (91613) and Tenable (73327). Similar entries are available at 7837, 11563, 12088 and 57803.

Productinfo

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB CVSS-B Score: 🔍
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CVSSv3info

VulDB Meta Base Score: 5.9
VulDB Meta Temp Score: 5.2

VulDB Base Score: 5.9
VulDB Temp Score: 5.2
VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv2info

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VulDB Base Score: 🔍
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Exploitinginfo

Class: Input validation
CWE: CWE-20
ATT&CK: Unknown

Local: Yes
Remote: No

Availability: 🔍
Status: Unproven

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

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Nessus ID: 73327
Nessus Name: SuSE 11.3 Security Update : sudo (SAT Patch Number 9044)
Nessus File: 🔍
Nessus Risk: 🔍
Nessus Family: 🔍
Nessus Port: 🔍

OpenVAS ID: 881892
OpenVAS Name: CentOS Update for sudo CESA-2014:0266 centos5
OpenVAS File: 🔍
OpenVAS Family: 🔍

Qualys ID: 🔍
Qualys Name: 🔍

Threat Intelligenceinfo

Interest: 🔍
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Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔍

Upgrade: sudo 1.8.5
Patch: sudo.ws
Config: Not Disable env_reset

Timelineinfo

12/03/2013 🔍
03/05/2014 +92 days 🔍
03/06/2014 +1 days 🔍
03/10/2014 +4 days 🔍
03/11/2014 +1 days 🔍
04/04/2014 +24 days 🔍
08/18/2015 +501 days 🔍
06/15/2021 +2128 days 🔍

Sourcesinfo

Advisory: sudo: security policy bypass when env_reset is disabled
Researcher: Sebastien Macke
Status: Confirmed
Confirmation: 🔍

CVE: CVE-2014-0106 (🔍)
X-Force: 91613 - Todd Miller sudo validate_env_vars privilege escalation, Medium Risk
SecurityTracker: 1029886 - Sudo validate_env_vars() Bug Lets Local Users Gain Elevated Privileges
Vulnerability Center: 52165 - Todd Miller Sudo 1.6.9-1.8.4 Local Bypass Restrictions Vulnerability via Crafted Environment Variable, Medium
SecurityFocus: 65997 - Todd Miller Sudo 'validate_env_vars()' Local Privilege Escalation Vulnerability

See also: 🔍

Entryinfo

Created: 03/10/2014 11:06
Updated: 06/15/2021 09:59
Changes: 03/10/2014 11:06 (54), 06/16/2017 09:02 (28), 06/15/2021 09:56 (1), 06/15/2021 09:59 (1)
Complete: 🔍

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