CVE-2022-25308: Gnu Fribidi Buffer Overflow Vulnerability

CVE-2022-25308 Overview

A stack-based buffer overflow vulnerability was discovered in the GNU Fribidi package, a library implementing the Unicode Bidirectional Algorithm. This flaw allows an attacker to pass a specially crafted file to applications utilizing the Fribidi library, potentially leading to memory corruption, information disclosure, or a denial of service condition.

Critical Impact

Successful exploitation of this stack-based buffer overflow can result in arbitrary code execution, memory leaks, or denial of service on affected systems running vulnerable versions of GNU Fribidi.

Affected Products

• GNU Fribidi (all vulnerable versions)
• Red Hat Enterprise Linux 8.0
• Red Hat Enterprise Linux 9.0

Discovery Timeline

• September 6, 2022 - CVE-2022-25308 published to NVD
• November 21, 2024 - Last updated in NVD database

Technical Details for CVE-2022-25308

Vulnerability Analysis

This vulnerability is classified under CWE-121 (Stack-based Buffer Overflow) and CWE-787 (Out-of-bounds Write). The flaw resides in the GNU Fribidi library, which provides an implementation of the Unicode Bidirectional Algorithm used for displaying text containing both left-to-right and right-to-left scripts.

The vulnerability occurs when the library processes specially crafted input files. Due to insufficient bounds checking during text processing operations, an attacker can trigger a stack-based buffer overflow condition. This memory corruption vulnerability requires local access to exploit, as the attacker must convince a user to open or process a malicious file through an application that relies on the Fribidi library.

The impact of successful exploitation includes the potential for arbitrary code execution with the privileges of the targeted application, memory information disclosure through memory leaks, or denial of service through application crashes.

Root Cause

The root cause of CVE-2022-25308 is improper bounds checking when processing bidirectional text data within the Fribidi library. When handling specially crafted input, the library fails to properly validate buffer boundaries, allowing data to be written beyond the allocated stack buffer space. This classic stack-based buffer overflow condition occurs due to insufficient input validation before memory write operations.

Attack Vector

The attack vector for this vulnerability requires local access with user interaction. An attacker must craft a malicious file containing specially formatted bidirectional text data and then convince a victim to process this file using an application that utilizes the Fribidi library.

The exploitation scenario typically involves:

1. The attacker creates a specially crafted file designed to trigger the buffer overflow
2. The victim opens or processes this file through a Fribidi-dependent application
3. The malicious input causes a stack-based buffer overflow during text processing
4. This can result in memory corruption, information leakage, or application crash

Technical details regarding the vulnerability can be found in the GitHub Issue #181 Discussion and the corresponding GitHub Pull Request #184 which addresses this issue.

Detection Methods for CVE-2022-25308

Indicators of Compromise

• Unexpected crashes in applications using the Fribidi library when processing text files
• Memory corruption errors or segmentation faults in processes utilizing libfribidi
• Unusual memory consumption patterns in applications handling bidirectional text

Detection Strategies

• Monitor for abnormal process terminations in applications that depend on the Fribidi library
• Implement file integrity monitoring on systems where Fribidi is installed to detect unauthorized modifications
• Use memory protection mechanisms such as Address Space Layout Randomization (ASLR) and stack canaries to detect exploitation attempts
• Deploy endpoint detection solutions capable of identifying buffer overflow exploitation patterns

Monitoring Recommendations

• Enable crash reporting and monitoring for applications utilizing GNU Fribidi
• Configure logging to capture application crashes and memory-related errors
• Monitor for suspicious file processing activities, particularly with unusual or malformed text files

How to Mitigate CVE-2022-25308

Immediate Actions Required

• Update GNU Fribidi to the latest patched version that addresses this vulnerability
• Apply vendor-supplied security patches for Red Hat Enterprise Linux 8.0 and 9.0
• Review and update any applications that bundle or depend on the Fribidi library
• Implement application whitelisting to restrict execution of potentially compromised binaries

Patch Information

The vulnerability has been addressed by the GNU Fribidi maintainers. Patches and fix details are available through the following resources:

• GitHub Pull Request #184 - Contains the official fix for this vulnerability
• Red Hat CVE-2022-25308 Advisory - Red Hat's security advisory with patch information
• Red Hat Bug Report #2047890 - Detailed bug tracking information

Organizations using Red Hat Enterprise Linux should apply the relevant security updates through their standard package management system.

Workarounds

• Restrict access to systems running vulnerable Fribidi versions to trusted users only
• Implement strict file validation before processing untrusted text files with Fribidi-dependent applications
• Consider disabling or removing Fribidi functionality in applications where bidirectional text support is not required
• Deploy application sandboxing to limit the impact of potential exploitation

# Check installed Fribidi version on Red Hat-based systems
rpm -qa | grep fribidi

# Update Fribidi package on RHEL/CentOS
sudo yum update fribidi

# Verify the update was applied
rpm -q fribidi --changelog | head -20