CVE-2010-2542 in Git
Summary
by MITRE
Stack-based buffer overflow in the is_git_directory function in setup.c in Git before 1.7.2.1 allows local users to gain privileges via a long gitdir: field in a .git file in a working copy.
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Analysis
by VulDB Data Team • 09/22/2021
The vulnerability identified as CVE-2010-2542 represents a critical stack-based buffer overflow flaw within the Git version control system that affects installations prior to 1.7.2.1. This security weakness resides in the is_git_directory function located within the setup.c source file, which processes gitdir: entries found in .git configuration files within working copies. The flaw manifests when Git encounters a malformed or excessively long gitdir: field specification, creating an exploitable condition that can be leveraged by local attackers to execute arbitrary code with elevated privileges. The vulnerability specifically targets the stack memory management during the parsing of git directory references, where insufficient bounds checking allows memory corruption to occur.
The technical exploitation of this vulnerability occurs through the manipulation of .git files within a working directory, where attackers can craft malicious gitdir: entries that exceed the allocated stack buffer size. This buffer overflow condition enables attackers to overwrite adjacent stack memory locations, potentially including return addresses and function pointers, which can be manipulated to redirect program execution flow. The flaw is classified as a stack-based buffer overflow, which directly maps to CWE-121, representing insufficient boundary checking in stack-based buffer operations. The vulnerability's exploitation requires local system access but can result in privilege escalation, as the Git process typically runs with the privileges of the user who owns the working copy, potentially allowing attackers to gain elevated system access.
From an operational perspective, this vulnerability poses significant risks to development environments and systems where Git is used extensively for version control operations. The attack surface includes any system running vulnerable Git versions where local users might have access to working directories or where Git repositories are managed with user-controlled .git files. The impact extends beyond simple code execution, as successful exploitation can lead to complete system compromise, data exfiltration, and persistence mechanisms within the affected environment. This vulnerability aligns with ATT&CK technique T1068, which covers 'Exploitation for Privilege Escalation' and T1548.001, 'Abuse Elevation Control Mechanism: Bypass User Access Controls', as attackers can leverage the privilege escalation capability to bypass normal access controls and gain elevated system privileges.
The recommended mitigation strategy involves immediate upgrading to Git version 1.7.2.1 or later, which contains the necessary patches to address the buffer overflow condition. System administrators should also implement comprehensive patch management processes to ensure all Git installations across development and production environments are updated promptly. Additional defensive measures include restricting write access to .git files and working directories, implementing proper file permission controls, and monitoring for suspicious .git file modifications. Organizations should also consider implementing runtime protections such as stack canaries or address space layout randomization to make exploitation more difficult, though these protections are secondary to the primary fix of updating to patched versions. The vulnerability serves as a reminder of the critical importance of input validation and memory safety practices in version control systems, particularly given their widespread use in development environments and the potential for privilege escalation through seemingly benign configuration file manipulations.