CVE-2024-2961

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Last Modified: UTC

Important Important Impact What does this mean?
8.8 CVSS v3 Base Score

Description

An out-of-bounds write flaw was found in the ISO-2022-CN-EXT plugin for glibc's iconv library. When converting from UCS4 charset, adding certain escape charterers is required to indicate where the charset was changed to the library. During this process, iconv improperly checks the boundaries of internal buffers, leading to a buffer overflow, which allows writing up to 3 bytes outside the desired memory location. This issue may allow an attacker to craft a malicious characters sequence that will trigger the out-of-bounds write and perform remote code execution, presenting a high impact to the Integrity, Confidentiality, and Availability triad.

Statement

The described vulnerability in the iconv() function of GNU C Library, particularly affecting ISO-2022-CN-EXT character set conversions, poses a important severity issue due to its potential for out-of-bound writes. Such buffer overflows can lead to arbitrary memory corruption, which can be exploited by attackers to execute arbitrary code, crash applications, or overwrite critical data structures, including neighboring variables. Given that the overflow can occur with specific, predictable values through SS2designation and SS3designation escape sequences, an attacker could craft malicious input to specifically trigger these overflows. Exploitation of this vulnerability could result in denial of service, privilege escalation, or even remote code execution, posing a significant threat to the security and integrity of affected systems.

Mitigation

This issue can be mitigated by removing the ISO-2022-CN-EXT from glibc-gconv-extra's modules configuration. This can be done by:

1) Verify if the module is loaded by running:

$ iconv -l | grep -E 'CN-?EXT'
ISO-2022-CN-EXT//
ISO2022CNEXT//

If the grep output looks like the above, ISO-2022-CN-EXT module is enabled.

2) Disabled the module by editing the file located at /usr/lib64/gconv/gconv-modules.d/gconv-modules-extra.conf and comment the following lines. For RHEL 7 the file that needs to be edited is /usr/lib64/gconv/gconv-modules. This step requires to be executed by a privileged user:

#       from                    to                      module          cost
alias   ISO2022CNEXT//          ISO-2022-CN-EXT//
module  ISO-2022-CN-EXT//       INTERNAL                ISO-2022-CN-EXT 1
module  INTERNAL                ISO-2022-CN-EXT//       ISO-2022-CN-EXT 1

For commenting those lines just add the '#' character at the beginning of mentioned lines:

#       from                    to                      module          cost
#alias  ISO2022CNEXT//          ISO-2022-CN-EXT//
#module ISO-2022-CN-EXT//       INTERNAL                ISO-2022-CN-EXT 1
#module INTERNAL                ISO-2022-CN-EXT//       ISO-2022-CN-EXT 1

3) Update the iconv cache by running:

sudo iconvconfig

4) Check if the module was disabled by running the first step again. This time ISO-2022-CN-EXT should not appear in the output.

Please notice that disabling the mentioned gconv module may lead applications relying in the affected module to fail in converting characters and should be used as a temporary mitigation before being able to fully update the affected package.

Additional Information

External References

Content from www.cve.org is not included.https://www.cve.org/CVERecord?id=CVE-2024-2961

Content from nvd.nist.gov is not included.https://nvd.nist.gov/vuln/detail/CVE-2024-2961

Content from www.openwall.com is not included.https://www.openwall.com/lists/oss-security/2024/04/17/9

Affected Packages and Issued Red Hat Security Errata

Products / Services Components State Errata
Red Hat Enterprise Linux 10 glibc Not affected
Red Hat Enterprise Linux 6 compat-glibc Not affected
Red Hat Enterprise Linux 6 glibc Out of support scope
Red Hat Enterprise Linux 6 nss_db Out of support scope
Red Hat Enterprise Linux 7 glibc Fixed RHSA-2024:3588
Red Hat Enterprise Linux 7 compat-glibc Not affected
Red Hat Enterprise Linux 8 glibc Fixed RHSA-2024:2722
Red Hat Enterprise Linux 8 glibc Fixed RHSA-2024:3269
Red Hat Enterprise Linux 8.2 Advanced Update Support glibc Fixed RHSA-2024:3464
Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support glibc Fixed RHSA-2024:3309
Unless explicitly stated as not affected, all previous versions of packages in any minor update stream of a product listed here should be assumed vulnerable, although may not have been subject to full analysis.

Common Vulnerability Scoring System (CVSS) Score Details

Important note

CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authorities (CNA) source for its products and services (see Red Hat classifications ).

CVSS v3 Score Breakdown Red Hat NVD
CVSS v3 Base Score 8.8
Attack Vector Network
Attack Complexity Low
Privileges Required Low
User Interaction None
Scope Unchanged
Confidentiality Impact High
Integrity Impact High
Availability Impact High

CVSS v3 Vector

Red Hat CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Acknowledgements

Red Hat would like to thank Charles Fol for reporting this issue.

Frequently Asked Questions

Why is Red Hat's CVSS v3 score or Impact different from other vendors?

 For open source software shipped by multiple vendors, the CVSS base scores may vary for each vendor's version depending on the version they ship, how they ship it, the platform, and even how the software is compiled. This makes scoring of vulnerabilities difficult for third-party vulnerability databases such as NVD that only provide a single CVSS base score for each vulnerability. Red Hat scores reflect how a vulnerability affects our products specifically.

For more information, see https://access.redhat.com/solutions/762393.

My product is listed as "Under investigation" or "Affected", when will Red Hat release a fix for this vulnerability?
  • "Under investigation" doesn't necessarily mean that the product is affected by this vulnerability. It only means that our Analysis Team is still working on determining whether the product is affected and how it is affected.
  • "Affected" means that our Analysis Team has determined that this product is affected by this vulnerability and might release a fix to address this in the near future.

What can I do if my product is listed as "Will not fix"?

 A "will not fix" status means that a fix for an affected product version is not planned or not possible due to complexity, which may create additional risk.

Available options depend mostly on the Impact of the vulnerability and the current Life Cycle phase of your product. Overall, you have the following options:
  • Upgrade to a supported product version that includes a fix for this vulnerability (recommended).
  • Apply a mitigation (if one exists).
  • Open a This content is not included.support case to request a prioritization of releasing a fix for this vulnerability.

What can I do if my product is listed as "Fix deferred"?

 A deferred status means that a fix for an affected product version is not guaranteed due to higher-priority development work.

Available options depend mostly on the Impact of the vulnerability and the current Life Cycle phase of your product. Overall, you have the following options:
  • Apply a mitigation (if one exists).
  • Open a This content is not included.support case to request a prioritization of releasing a fix for this vulnerability.
  • Red Hat Engineering focuses on addressing high-priority issues based on their complexity or limited lifecycle support. Therefore, lower-priority issues will not receive immediate fixes.

What is a mitigation?

 A mitigation is an action that can be taken to reduce the impact of a security vulnerability, without deploying any fixes.

I have a Red Hat product but it is not in the above list, is it affected?

 The listed products were found to include one or more of the components that this vulnerability affects. These products underwent a thorough evaluation to determine their affectedness by this vulnerability. Note that layered products (such as container-based offerings) that consume affected components from any of the products listed in this table may be affected and are not represented.

Why is my security scanner reporting my product as vulnerable to this vulnerability even though my product version is fixed or not affected?

 In order to maintain code stability and compatibility, Red Hat usually does not rebase packages to entirely new versions. Instead, we backport fixes and new features to an older version of the package we distribute. This can result in some security scanners that only consider the package version to report the package as vulnerable. To avoid this, we suggest that you use an approved vulnerability scanner from our This content is not included.Red Hat Vulnerability Scanner Certification program.

My product is listed as "Out of Support Scope". What does this mean?

 When a product is listed as "Out of Support Scope", it means a vulnerability with the impact level assigned to this CVE is no longer covered by its current support lifecycle phase. The product has been identified to contain the impacted component, but analysis to determine whether it is affected or not by this vulnerability was not performed. The product should be assumed to be affected. Customers are advised to apply any mitigation options documented on this page, consider removing or disabling the impacted component, or upgrade to a supported version of the product that has an update available.