CVE-2007-4404 in ircu
Summary
by MITRE
ircu 2.10.12.01 allows remote attackers to (1) cause a denial of service (flood wallops) by joining two channels with certain long names that differ in the final character, which triggers a protocol violation and (2) cause a denial of service (daemon crash) via a "J 0:#channel" message on a channel without an apass; and (3) allows remote authenticated operators to cause a denial of service (daemon crash) via a remote "names -D" command.
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Analysis
by VulDB Data Team • 09/07/2018
The CVE-2007-4404 vulnerability affects ircu 2.10.12.01, a widely used Internet Relay Chat server implementation that has been fundamental to many IRC networks since its release. This vulnerability represents a significant security flaw in the server's handling of channel names and protocol messages, creating multiple attack vectors that can compromise system availability and stability. The vulnerability is particularly concerning as it affects core IRC server functionality and can be exploited by both unauthenticated and authenticated attackers, making it a critical issue for network administrators maintaining IRC infrastructure.
The primary technical flaw involves improper validation of channel names and protocol message handling within the ircu server implementation. When attackers join two channels with specific long names that differ only in their final character, the server triggers a protocol violation that results in a flood of wallops messages. This occurs because the server fails to properly handle the edge case where channel names approach maximum length limits while maintaining unique identifiers, leading to excessive message generation that can overwhelm the server's communication channels and cause denial of service conditions. The vulnerability operates at the protocol level and aligns with CWE-129, which addresses improper validation of input length, and CWE-400, which covers resource exhaustion through excessive message handling.
A second vector involves the specific "J 0:#channel" message format that can crash the daemon when executed against channels without an apass parameter. This represents a classic buffer overflow or improper state handling vulnerability where the server does not adequately validate the channel access parameters before processing the join command. The crash occurs because the server's internal state management fails to properly account for channels without access passwords, leading to memory corruption or invalid pointer dereference conditions that terminate the daemon process. This vulnerability demonstrates weaknesses in input validation and error handling that can be exploited to cause system instability, and it relates to CWE-125, which covers out-of-bounds read conditions, and CWE-248, which addresses exposure of exception information.
The third attack vector involves authenticated operators exploiting a "names -D" command to cause daemon crashes, highlighting a privilege escalation or command injection vulnerability within the server's operator access controls. This particular flaw suggests that the server's command processing logic for operator-level commands does not properly validate or sanitize input parameters, allowing authenticated users to execute potentially harmful operations. The vulnerability occurs within the names command processing module and indicates insufficient input validation and access control enforcement mechanisms that are critical for maintaining server stability when dealing with privileged operations.
The operational impact of these vulnerabilities is severe and multifaceted, as they can compromise the availability and stability of entire IRC networks. The flood wallops attack can render the server unusable for legitimate users by overwhelming communication channels and potentially causing network saturation. The daemon crash vulnerabilities can result in complete service interruption, requiring manual intervention to restart the server and potentially leading to loss of user connections and session data. These vulnerabilities are particularly dangerous in large IRC networks where a single compromised server can affect thousands of users and potentially disrupt communication channels used for critical coordination activities.
Mitigation strategies should focus on immediate patching and implementation of input validation controls. Network administrators should upgrade to ircu versions that address these specific vulnerabilities, as the original 2.10.12.01 release contains known flaws that have been documented and resolved in subsequent versions. Additionally, implementing rate limiting and connection monitoring can help detect and prevent exploitation attempts. The vulnerabilities align with ATT&CK technique T1499.004, which covers network disruption through resource exhaustion, and T1070.004, which covers indicator removal through deletion of system logs. Proper input sanitization and validation should be implemented at multiple levels, including channel name validation, protocol message parsing, and operator command processing. Organizations should also consider implementing intrusion detection systems to monitor for suspicious protocol patterns and maintain regular backups to ensure rapid recovery from potential daemon crashes.