CVE-2015-3277 in mod_nss
Summary
by MITRE
The mod_nss module before 1.0.11 in Fedora allows remote attackers to obtain cipher lists due to incorrect parsing of multi-keyword cipherstring.
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Analysis
by VulDB Data Team • 11/25/2024
The vulnerability identified as CVE-2015-3277 affects the mod_nss module in Fedora versions prior to 1.0.11, presenting a significant security risk through improper handling of cipher string parsing. This issue specifically manifests when the module processes multi-keyword cipher strings, creating a condition where remote attackers can potentially extract sensitive cipher information from the system. The flaw resides in the module's inability to correctly parse complex cipher configurations that contain multiple keywords, leading to information disclosure vulnerabilities. This vulnerability operates at the intersection of cryptographic protocol implementation and security configuration management, where the incorrect parsing behavior directly impacts the confidentiality of cryptographic parameters.
The technical implementation flaw stems from the mod_nss module's inadequate handling of cipher string syntax when multiple keywords are present in the configuration. When processing cipher specifications that contain multiple keywords, the module fails to properly separate and interpret each component of the cipher string, resulting in a parsing mechanism that can leak cipher list information to unauthorized parties. This incorrect parsing behavior represents a deviation from proper cryptographic configuration management practices and violates security principles related to information hiding and access control. The vulnerability is particularly concerning because it allows attackers to gain knowledge about the cryptographic capabilities and preferences of the affected system without requiring authentication or direct access to the server configuration files.
The operational impact of this vulnerability extends beyond simple information disclosure, as it can enable more sophisticated attacks by providing adversaries with insights into the cryptographic environment. Attackers who can obtain cipher lists may use this information to tailor subsequent attacks, potentially targeting weaker cipher suites or exploiting known vulnerabilities in specific cryptographic algorithms. The remote nature of this attack vector means that an attacker can exploit the vulnerability from anywhere on the network, making it particularly dangerous for web servers and other publicly accessible systems. This vulnerability aligns with CWE-200, which covers information exposure, and can contribute to broader cryptographic attack strategies that leverage knowledge of system capabilities to improve attack success rates.
Organizations affected by this vulnerability should prioritize immediate remediation through updating to mod_nss version 1.0.11 or later, which contains the necessary fixes for the cipher string parsing issue. System administrators should also conduct thorough configuration reviews to ensure that cipher string specifications are properly formatted and do not contain multiple keywords that could trigger the parsing error. The mitigation strategy should include monitoring for any unusual access patterns that might indicate exploitation attempts and implementing additional security controls such as network segmentation and intrusion detection systems. From an ATT&CK perspective, this vulnerability maps to techniques involving information gathering and credential access, as it enables adversaries to collect intelligence about cryptographic configurations that could be used in subsequent phases of an attack campaign.