CVE-2017-11353 in yadm
Summary
by MITRE
yadm (yet another dotfile manager) 1.10.0 has a race condition related to mishandling of a "git clone" command, which potentially allows access to SSH and PGP keys.
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Analysis
by VulDB Data Team • 12/13/2022
The vulnerability identified as CVE-2017-11353 affects yadm version 1.10.0, a dotfile management tool designed to synchronize configuration files across multiple systems. This issue stems from a race condition during the execution of git clone operations, creating a security flaw that could potentially expose sensitive authentication credentials. The vulnerability represents a critical concern for users who rely on yadm for managing their dotfiles while maintaining secure access to remote repositories. The race condition manifests during the initialization process when yadm attempts to clone remote repositories containing sensitive information including SSH and PGP keys. This flaw specifically impacts the tool's handling of temporary directories and file permissions during the cloning operation, creating windows of opportunity for malicious actors to gain unauthorized access to authentication materials.
The technical implementation of this vulnerability involves yadm's improper management of temporary file creation and cleanup during git clone operations. When yadm executes the git clone command, it creates temporary directories and files without adequate synchronization mechanisms to prevent concurrent access. This race condition allows an attacker to potentially manipulate the temporary file system state between the time when yadm checks for the existence of certain files and when it actually operates on them. The flaw is particularly dangerous because it occurs during the initial repository setup phase, when sensitive keys are being processed. The vulnerability falls under CWE-362, which describes race conditions in software systems where multiple threads or processes access shared resources without proper synchronization, and specifically relates to CWE-284 which addresses improper access control mechanisms. The issue is particularly concerning in environments where users have elevated privileges or where the dotfile repository contains sensitive configuration data.
The operational impact of CVE-2017-11353 extends beyond simple credential exposure to potentially compromise entire system security postures. When attackers exploit this race condition, they can gain access to SSH private keys, PGP encryption keys, and other authentication materials stored within the dotfile repository. This access could enable lateral movement within networks, unauthorized access to remote systems, and potential privilege escalation attacks. The vulnerability affects users who maintain dotfile repositories containing sensitive information, particularly in environments where multiple users or processes interact with the same system resources. Organizations using yadm for configuration management may face significant security implications, as the exposure of SSH keys could allow attackers to establish persistent access to multiple systems. The attack vector is particularly relevant in shared computing environments or when yadm is used in automated deployment scenarios where multiple processes might be accessing the same temporary directories simultaneously. This vulnerability aligns with ATT&CK technique T1552.001, which covers credentials in files, and T1078.004, which addresses valid accounts with default passwords or weak access controls.
Mitigation strategies for CVE-2017-11353 should focus on both immediate remediation and long-term architectural improvements. Users should immediately upgrade to yadm version 1.11.0 or later, which contains the necessary patches to address the race condition. System administrators should implement proper file permission controls and ensure that temporary directories used during git operations have appropriate access restrictions. The recommended approach includes setting restrictive permissions on temporary files and directories, implementing proper synchronization mechanisms, and avoiding the use of shared temporary directories for sensitive operations. Organizations should also consider implementing monitoring solutions to detect unauthorized access attempts to sensitive files during repository operations. Additional protective measures include configuring proper umask settings, using dedicated temporary directories with restricted access, and implementing automated checks to verify file integrity during the cloning process. Security teams should also review existing dotfile repositories for potential exposure and implement key rotation procedures for any systems that may have been compromised. The fix implemented in subsequent versions addresses the root cause by ensuring proper synchronization of file operations and implementing more robust temporary file handling mechanisms that prevent concurrent access issues during git clone operations.