CVE-2011-5268 in Bip
Summary
by MITRE
connection.c in Bip before 0.8.9 does not properly close sockets, which allows remote attackers to cause a denial of service (file descriptor consumption and crash) via multiple failed SSL handshakes, a different vulnerability than CVE-2013-4550. NOTE: this issue was SPLIT from CVE-2013-4550 because it is a different type of issue.
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Analysis
by VulDB Data Team • 01/18/2022
The vulnerability identified as CVE-2011-5268 affects the Bip IRC client version 0.8.8 and earlier, specifically within the connection.c module. This flaw represents a classic resource management issue that can be exploited to cause denial of service conditions through improper socket handling. The Bip IRC client is a command-line interface tool that allows users to connect to IRC networks, making it a potential target for attackers seeking to disrupt network communications or compromise system stability.
The technical flaw stems from the improper closure of socket connections within the connection.c file, which is responsible for managing network connections in the Bip client. When multiple failed SSL handshakes occur, the application fails to properly close the associated file descriptors, leading to a gradual consumption of available file handles. This socket leak occurs because the program does not adequately clean up network resources after failed authentication attempts, creating a scenario where each unsuccessful SSL handshake consumes additional file descriptors without proper release. The vulnerability is particularly concerning because it operates at the network protocol level, where resource exhaustion can cascade into system-wide stability issues.
The operational impact of this vulnerability manifests as a denial of service condition that can be triggered by remote attackers through carefully crafted sequences of failed SSL handshakes. As file descriptors accumulate without proper closure, the system eventually exhausts its available socket handles, causing the Bip client to crash or become unresponsive. This type of resource exhaustion attack can be particularly effective in environments where the IRC client is frequently used or exposed to network traffic, as the accumulation of leaked file descriptors can occur rapidly. The vulnerability creates a scenario where legitimate users may be unable to establish new connections due to resource constraints, effectively disrupting service availability.
From a cybersecurity perspective, this vulnerability aligns with CWE-404, which addresses improper resource cleanup or release, and relates to the broader category of resource leak vulnerabilities that frequently appear in network applications. The attack pattern follows the typical methodology described in ATT&CK technique T1499.004 for network denial of service attacks, where adversaries exploit application flaws to consume system resources and cause service disruption. The vulnerability's classification as a different issue from CVE-2013-4550 indicates that while both relate to connection handling, they represent distinct attack vectors with different technical implementations and exploitation methods. This distinction is important for security teams to understand when implementing mitigation strategies and conducting vulnerability assessments.
The recommended mitigations for this vulnerability involve upgrading to Bip version 0.8.9 or later, which contains the necessary code fixes to properly close sockets after failed SSL handshakes. Administrators should also implement network monitoring to detect unusual patterns of failed connections that may indicate exploitation attempts. Additionally, system administrators can consider implementing connection rate limiting and resource limits to prevent complete exhaustion of file descriptors. The fix implemented in version 0.8.9 should ensure proper socket cleanup regardless of SSL handshake success or failure, thereby preventing the accumulation of leaked file descriptors that leads to the denial of service condition.