CVE-2006-0458 in irssi
Summary
by MITRE
The DCC ACCEPT command handler in irssi before 0.8.9+0.8.10rc5-0ubuntu4.1 in Ubuntu Linux, and possibly other distributions, allows remote attackers to cause a denial of service (application crash) via certain crafted arguments in a DCC command.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 06/15/2019
The vulnerability described in CVE-2006-0458 affects the irssi IRC client software, specifically targeting the DCC ACCEPT command handler in versions prior to 0.8.9 and 0.8.10rc5. This represents a classic buffer overflow condition that manifests through improper input validation within the DCC (Direct Client-to-Client) protocol implementation. The DCC protocol is commonly used in IRC networks for file transfers, chat sessions, and other direct communications between clients. When a malicious remote user sends specially crafted arguments to the DCC ACCEPT command, the irssi client fails to properly validate these inputs, leading to memory corruption that ultimately results in application crash and denial of service.
The technical flaw stems from inadequate bounds checking and input sanitization within the command parsing mechanism of irssi's DCC subsystem. According to CWE-121, this vulnerability falls under the category of stack-based buffer overflow conditions where insufficient validation allows attackers to overwrite adjacent memory locations. The vulnerability is particularly concerning because it operates at the protocol level of IRC communications, meaning that an attacker can exploit this weakness without requiring any special privileges or authentication. The DCC ACCEPT command is designed to handle incoming DCC connections, but when malformed arguments are provided, the software fails to properly handle the data structure, causing the application to terminate unexpectedly. This type of vulnerability aligns with ATT&CK technique T1499.004, which involves network denial of service attacks through application-level exploitation.
The operational impact of this vulnerability extends beyond simple service disruption, as it can be leveraged by attackers to systematically degrade IRC services within a network. When multiple users are affected by this denial of service condition, it can lead to widespread disruption of communication channels that rely on irssi clients. The vulnerability is particularly dangerous in environments where irssi is used for critical communications, such as system administration channels, development team coordination, or any scenario where persistent IRC connectivity is essential. Attackers can exploit this weakness by simply connecting to an IRC server and sending the malicious DCC ACCEPT command to any user running the vulnerable irssi version, making this a particularly effective vector for low-effort disruption attacks. The vulnerability affects not only Ubuntu Linux systems but potentially other distributions that ship the same vulnerable irssi versions, highlighting the widespread nature of the issue.
Mitigation strategies for this vulnerability focus primarily on immediate software updates and patches, as this represents a well-known issue that was addressed in subsequent releases of irssi. System administrators should prioritize updating their irssi installations to versions 0.8.9 or later, which contain the necessary fixes for the input validation issues. Additionally, implementing network-level controls such as firewall rules that restrict DCC communication or monitoring for suspicious DCC command patterns can provide additional layers of protection. The vulnerability also underscores the importance of input validation and proper memory management in client-side applications, particularly those handling network protocols where untrusted data is received from external sources. Organizations should also consider implementing automated patch management systems to ensure timely updates and reduce the window of exposure to known vulnerabilities. This case study exemplifies why continuous security testing and validation of input handling mechanisms are essential components of secure software development practices.