CVE-2013-2145 in Perl
Summary
by MITRE
The cpansign verify functionality in the Module::Signature module before 0.72 for Perl allows attackers to bypass the signature check and execute arbitrary code via a SIGNATURE file with a "special unknown cipher" that references an untrusted module in Digest/.
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Analysis
by VulDB Data Team • 12/27/2024
The vulnerability identified as CVE-2013-2145 affects the Module::Signature Perl module version 0.72 and earlier, presenting a critical security flaw in the cpansign verify functionality. This issue stems from improper handling of signature verification processes where attackers can exploit a specific condition involving a "special unknown cipher" within SIGNATURE files. The vulnerability creates a path for privilege escalation and arbitrary code execution by manipulating the Digest/ module references within the signature verification workflow.
The technical flaw resides in how the Module::Signature module processes cryptographic signatures during verification. When encountering a SIGNATURE file containing a special unknown cipher, the module fails to properly validate the referenced Digest/ module components, allowing attackers to inject malicious code through crafted signature files. This represents a classic case of insecure deserialization and improper input validation, where the system blindly trusts module references without adequate cryptographic integrity checks. The vulnerability operates at the level of Perl module security and cryptographic verification, enabling attackers to bypass security controls that should prevent execution of untrusted code.
The operational impact of this vulnerability is severe, as it allows remote attackers to execute arbitrary code on systems running vulnerable versions of Perl with the affected module installed. This creates a significant risk for Perl developers and system administrators who rely on module signature verification for security. Attackers can craft malicious SIGNATURE files that appear legitimate to the verification process but actually contain code that executes when the module attempts to process the Digest/ references. The vulnerability affects systems where Perl modules are installed from untrusted sources, particularly in environments where module signature verification is expected to provide security boundaries.
Mitigation strategies for CVE-2013-2145 involve immediate upgrading of the Module::Signature module to version 0.72 or later, where the vulnerability has been addressed through improved signature verification logic. System administrators should also implement strict module installation policies that prevent installation of unsigned or untrusted modules, particularly those from public repositories. Additional protective measures include monitoring for suspicious SIGNATURE file modifications and implementing automated security scanning tools that can detect malformed signature files. The vulnerability aligns with CWE-20: Improper Input Validation and follows ATT&CK technique T1059.007 for execution through Perl scripts, emphasizing the need for proper cryptographic verification and input sanitization in security-critical Perl applications. Organizations should also consider implementing network segmentation and privilege separation to limit the potential impact of successful exploitation attempts.