CVE-2018-1000802 in CPython
Summary
by MITRE
Python Software Foundation Python (CPython) version 2.7 contains a CWE-77: Improper Neutralization of Special Elements used in a Command ('Command Injection') vulnerability in shutil module (make_archive function) that can result in Denial of service, Information gain via injection of arbitrary files on the system or entire drive. This attack appear to be exploitable via Passage of unfiltered user input to the function. This vulnerability appears to have been fixed in after commit add531a1e55b0a739b0f42582f1c9747e5649ace.
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Analysis
by VulDB Data Team • 05/16/2023
The vulnerability identified as CVE-2018-1000802 represents a critical command injection flaw in Python 2.7's shutil module, specifically within the make_archive function. This issue falls under CWE-77, which categorizes improper neutralization of special elements used in command construction. The vulnerability stems from the function's failure to properly sanitize user input, creating an avenue for malicious actors to inject arbitrary commands into the system. The flaw exists because the make_archive function directly incorporates user-supplied parameters into shell commands without adequate validation or escaping mechanisms, making it susceptible to exploitation through carefully crafted inputs that can manipulate the underlying command execution flow.
The operational impact of this vulnerability extends beyond simple command injection to encompass serious security implications including potential denial of service conditions, unauthorized information disclosure, and the ability to execute arbitrary file operations on the target system. Attackers can leverage this vulnerability to gain access to arbitrary files, potentially leading to complete system compromise. The risk is particularly severe because Python 2.7, while deprecated, was widely used in production environments, meaning that numerous systems could be vulnerable to exploitation. The vulnerability's exploitability is heightened by the fact that it requires only passage of unfiltered user input to the vulnerable function, making it accessible to attackers with minimal technical sophistication.
This vulnerability aligns with several ATT&CK framework techniques including T1059.001 (Command and Scripting Interpreter: PowerShell) and T1068 (Exploitation for Privilege Escalation) as it enables attackers to execute arbitrary commands with the privileges of the Python process. The fix implemented in commit add531a1e55b0a739b0f42582f1c9747e5649ace demonstrates the importance of proper input validation and command construction in preventing such vulnerabilities. Organizations should prioritize immediate remediation by upgrading to a supported Python version or applying the specific patch that addresses the improper neutralization of command arguments in the shutil module. Additionally, implementing proper input validation, using parameterized commands instead of string concatenation, and conducting regular security audits of code that interacts with system commands can significantly reduce the risk of similar vulnerabilities.
The broader implications of this vulnerability highlight the critical importance of secure coding practices and the dangers of relying on deprecated software versions. Python 2.7 reached end-of-life in January 2020, yet many systems continued to operate with it due to legacy dependencies, creating persistent security gaps. This vulnerability serves as a reminder of how seemingly minor oversights in command construction can result in catastrophic security consequences. The remediation process should include not only patching the immediate vulnerability but also conducting comprehensive audits of all codebases to identify similar patterns of insecure command execution. Security teams must also implement robust monitoring and incident response procedures to detect and respond to exploitation attempts against known vulnerabilities. The vulnerability's persistence in older Python versions underscores the necessity of maintaining up-to-date software inventory and implementing automated patch management processes to prevent similar issues from arising in the future.