CVE-2011-4091 in net6
Summary
by MITRE
The libobby server in inc/server.hpp in libnet6 (aka net6) before 1.3.14 does not perform authentication before checking the user name, which allows remote attackers to obtain sensitive information such as server-usage patterns by a particular user and color preferences.
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Analysis
by VulDB Data Team • 03/11/2022
The vulnerability identified as CVE-2011-4091 resides within the libobby server implementation in the inc/server.hpp file of the libnet6 library, commonly known as net6. This issue affects versions prior to 1.3.14 and represents a significant security flaw in the authentication mechanism. The root cause lies in the server's improper order of operations where it validates user names before enforcing proper authentication checks. This design flaw creates a window of opportunity for malicious actors to exploit the system's security controls.
The technical implementation of this vulnerability stems from a violation of proper access control principles where the server processes user identification information without first verifying the legitimacy of the user attempting to access the system. According to CWE-284, this represents an inadequate access control mechanism that allows unauthorized access to sensitive information. The flaw specifically manifests as a failure to implement mandatory access controls before performing user validation operations, creating a scenario where attackers can bypass authentication requirements.
Operationally, this vulnerability enables remote attackers to gather sensitive information about user behavior patterns and preferences without proper authorization. The disclosed information includes server usage patterns and color preferences, which while seemingly benign, can provide attackers with valuable insights into user habits and potentially aid in more sophisticated social engineering attacks. From an ATT&CK framework perspective, this vulnerability maps to T1083 (File and Directory Discovery) and T1566 (Phishing for Information) as it allows for information gathering that can be leveraged in broader attack campaigns.
The impact of this vulnerability extends beyond simple information disclosure, as the collected data about user preferences and usage patterns can be used to build detailed profiles of system users. This information can be particularly valuable in targeted attacks where attackers seek to understand user behavior to craft more convincing social engineering attempts. The vulnerability essentially allows for passive reconnaissance that can inform future attack vectors and increase the effectiveness of subsequent exploitation efforts.
Mitigation strategies for this vulnerability require immediate patching of affected systems to version 1.3.14 or later, which addresses the authentication order issue. Organizations should also implement network segmentation to limit access to affected services and consider implementing additional monitoring for unusual access patterns. The fix should ensure that proper authentication mechanisms are enforced before any user identification or preference data is processed, aligning with security best practices and proper access control implementation as recommended by industry standards including those outlined in the NIST Cybersecurity Framework and ISO 27001 security controls.