CVE-2015-8969 in git-fastclone
Summary
by MITRE
git-fastclone before 1.0.5 passes user modifiable strings directly to a shell command. An attacker can execute malicious commands by modifying the strings that are passed as arguments to "cd " and "git clone " commands in the library.
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Analysis
by VulDB Data Team • 09/29/2022
The vulnerability identified as CVE-2015-8969 affects git-fastclone versions prior to 1.0.5, representing a critical command injection flaw that stems from improper input validation within the library's execution flow. This issue manifests when the software processes user-modifiable strings and directly incorporates them into shell commands without adequate sanitization or escaping mechanisms. The flaw specifically impacts the handling of strings passed to shell commands, particularly those involving "cd " and "git clone " operations, creating an environment where malicious actors can manipulate the execution flow through crafted input sequences.
The technical implementation of this vulnerability aligns with CWE-78, which categorizes improper neutralization of special elements used in OS commands, and more specifically with CWE-94, which addresses improper control of generation of code. The vulnerability operates by allowing untrusted input to be concatenated directly into shell command strings, bypassing normal security boundaries that would typically prevent arbitrary command execution. When an attacker modifies strings that are subsequently used in shell contexts, they can inject malicious commands that will execute with the privileges of the user running the git-fastclone utility. This type of injection vulnerability is particularly dangerous in automated environments where the utility might be invoked with elevated privileges.
The operational impact of this vulnerability extends beyond simple command execution, as it can enable attackers to perform a wide range of malicious activities including data exfiltration, system compromise, and persistence establishment. The vulnerability is particularly concerning in continuous integration environments or automated deployment systems where git-fastclone might be used to clone repositories, as attackers could potentially inject commands that modify the build process, steal credentials, or establish backdoors. The attack surface is broadened by the fact that the vulnerability affects the library's core functionality, meaning that any application or system utilizing git-fastclone could be compromised, regardless of the specific implementation details.
Mitigation strategies for CVE-2015-8969 should focus on implementing proper input validation and sanitization mechanisms to prevent user-modifiable strings from being directly incorporated into shell commands. The recommended approach involves using parameterized command execution rather than string concatenation, which aligns with the ATT&CK technique T1059.001 for command and scripting interpreter. Organizations should upgrade to git-fastclone version 1.0.5 or later, which includes proper input sanitization. Additional protective measures include implementing proper access controls to limit who can modify the strings passed to the library, using restricted user accounts for running the utility, and employing input validation frameworks that can detect and block suspicious command sequences. The vulnerability also highlights the importance of following secure coding practices that avoid shell injection vectors entirely by using safe APIs and avoiding direct shell command construction with untrusted data sources.