CVE-2009-2946 in devscripts
Summary
by MITRE
Eval injection vulnerability in scripts/uscan.pl before Rev 1984 in devscripts allows remote attackers to execute arbitrary Perl code via crafted pathnames on distribution servers for upstream source code used in Debian GNU/Linux packages.
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 08/21/2021
The CVE-2009-2946 vulnerability represents a critical server-side evaluation injection flaw in the devscripts package's uscan.pl script, which operates as a component for tracking upstream source code updates in Debian GNU/Linux distributions. This vulnerability exists in versions of devscripts prior to Rev 1984 and specifically affects the automated package update mechanism that developers rely upon to maintain their software repositories. The flaw stems from insufficient input validation and sanitization within the script's handling of pathname data received from distribution servers, creating a pathway for malicious actors to inject and execute arbitrary Perl code on systems running vulnerable versions of the software.
The technical exploitation of this vulnerability occurs when the uscan.pl script processes upstream source code pathnames from distribution servers without proper sanitization of user-supplied input. Attackers can craft malicious pathnames that contain embedded Perl code which gets evaluated by the script during its normal operation. This evaluation process constitutes a classic code injection vulnerability that falls under CWE-94, which specifically addresses the execution of arbitrary code due to improper input validation and dynamic code evaluation. The vulnerability is particularly dangerous because it operates at the server level where the uscan.pl script is designed to process and validate upstream source code, making it an attractive target for attackers seeking persistent access to package repositories.
The operational impact of this vulnerability extends beyond simple code execution, as it can enable attackers to compromise entire package repositories and potentially affect thousands of downstream Debian systems. When attackers successfully exploit this vulnerability, they gain the ability to inject malicious code into the package update process, which can lead to supply chain compromise and persistent backdoor access. The attack vector requires remote access to distribution servers that serve upstream source code to Debian package maintainers, making it a significant concern for repository administrators and security teams responsible for maintaining package integrity. This vulnerability aligns with ATT&CK technique T1059.007 for execution through scripting and T1505.003 for server-side code injection, demonstrating the multi-layered nature of the attack surface.
Mitigation strategies for CVE-2009-2946 primarily focus on immediate version updates to devscripts package versions that contain the necessary patches and input validation improvements. System administrators should prioritize upgrading to devscripts versions that include proper input sanitization measures and eliminate the unsafe code evaluation patterns that enabled this vulnerability. Additionally, implementing network-level controls such as firewall rules that restrict access to distribution servers and monitoring for unusual pathname patterns can provide additional defense layers. Organizations should also consider implementing automated security scanning tools that can detect similar input validation flaws in other scripts and applications within their infrastructure. The vulnerability serves as a reminder of the importance of proper input validation and the dangers of dynamic code evaluation in server-side applications, particularly those handling user-supplied data from external sources.