CVE-2015-0839 in Linux Imaging
Summary
by MITRE
The hp-plugin utility in HP Linux Imaging and Printing (HPLIP) makes it easier for man-in-the-middle attackers to execute arbitrary code by leveraging use of a short GPG key id from a keyserver to verify print plugin downloads.
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Analysis
by VulDB Data Team • 12/02/2024
The vulnerability identified as CVE-2015-0839 resides within the hp-plugin utility component of HP Linux Imaging and Printing (HPLIP) software suite, presenting a significant security risk that undermines the integrity of print plugin downloads. This flaw specifically exploits the utility's reliance on GPG key verification mechanisms during the download process, creating an avenue for malicious actors to compromise system security. The vulnerability demonstrates a critical weakness in the software's trust model and cryptographic verification procedures.
The technical implementation of this vulnerability stems from the hp-plugin utility's practice of accepting short GPG key identifiers obtained from key servers for verifying print plugin authenticity. This approach fundamentally weakens the security posture by utilizing key identifiers that are significantly shorter than recommended cryptographic key lengths. Attackers can exploit this weakness through man-in-the-middle attacks by intercepting network traffic and substituting legitimate plugin downloads with malicious payloads. The short key identifiers create a reduced cryptographic entropy that makes key collision attacks more feasible, allowing adversaries to generate forged signatures that appear legitimate to the verification process. This vulnerability directly relates to CWE-327, which addresses the use of weak cryptographic algorithms and key sizes, and represents a failure in proper key management practices.
The operational impact of this vulnerability extends beyond simple code execution capabilities to encompass full system compromise potential. When attackers successfully exploit this weakness, they can install malicious plugins that execute arbitrary code with the privileges of the user running the hp-plugin utility. This creates opportunities for privilege escalation, persistent backdoor installation, and data exfiltration from compromised systems. The vulnerability affects systems running HPLIP versions that utilize the problematic verification mechanism, potentially exposing numerous networked printing environments to attack. Organizations relying on HP printing solutions for their operations face significant risk of unauthorized access and system infiltration through this vector, particularly in environments where network traffic interception is possible.
Mitigation strategies for CVE-2015-0839 should prioritize immediate software updates to patched versions of HPLIP that address the weak GPG key verification implementation. System administrators should implement network monitoring to detect suspicious download activities and verify the integrity of all plugin installations through alternative verification methods. The use of full GPG key fingerprints instead of short identifiers should be enforced across all verification processes, aligning with best practices outlined in security standards such as those recommended by the OpenPGP specification. Network segmentation and firewall rules can help reduce attack surface by limiting access to key servers and restricting plugin download capabilities to trusted sources. Additionally, implementing network intrusion detection systems to monitor for man-in-the-middle attack patterns and conducting regular security audits of printing infrastructure will help identify and remediate similar vulnerabilities in related components. The remediation approach should also include educating users about the risks of downloading unverified software components and maintaining updated security configurations for all system components involved in the printing ecosystem.