CVE-2004-0605 in IRCD
Summary
by MITRE
non-registered irc users using (1) ircd-hybrid 7.0.1 and earlier (2) ircd-ratbox 1.5.1 and earlier or (3) ircd-ratbox 2.0rc6 and earlier do not have a rate-limit imposed which could allow remote attackers to cause a denial of service by repeatedly making requests which are slowly dequeued.
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Analysis
by VulDB Data Team • 11/18/2024
The vulnerability described in CVE-2004-0605 represents a significant denial of service weakness in several popular internet relay chat implementations including ircd-hybrid 7.0.1 and earlier versions, ircd-ratbox 1.5.1 and earlier versions, and ircd-ratbox 2.0rc6 and earlier versions. This flaw specifically targets unregistered users who can exploit the absence of rate limiting mechanisms to overwhelm the server with repeated connection requests that are processed slowly through the system queue. The vulnerability stems from the lack of proper access control and resource management for anonymous users, creating an exploitable condition that allows malicious actors to consume server resources without proper throttling.
The technical implementation of this vulnerability exploits the fundamental design flaw in how these ircd implementations handle unauthenticated connections. When users connect to the irc server without proper registration, the system fails to enforce rate limiting controls that would normally restrict the frequency of connection attempts or request processing. This creates a scenario where an attacker can continuously submit requests that are queued for processing but handled at a slow pace, effectively consuming server resources and network bandwidth. The slow dequeuing mechanism means that each request remains in the processing queue for extended periods, preventing legitimate users from accessing the service and creating a resource exhaustion condition.
From an operational impact perspective, this vulnerability enables remote attackers to conduct effective denial of service attacks against irc servers without requiring any special privileges or authentication credentials. The attack can be executed from anywhere on the internet and does not depend on specific network conditions or complex exploitation techniques. The slow processing nature of the queue means that the server gradually becomes overwhelmed with pending requests, leading to service degradation or complete unavailability. This type of attack directly violates the availability principle of the CIA triad and can severely impact communication infrastructure that relies on irc services for real-time messaging and collaboration.
The vulnerability aligns with CWE-400 which describes "Uncontrolled Resource Consumption" and specifically relates to improper restriction of excessive CPU or memory usage. From an ATT&CK framework perspective, this represents a resource exhaustion attack pattern that falls under the technique of "Resource Exhaustion" within the broader category of "Denial of Service". The attack leverages the weakness in the server's access control mechanisms to exploit the lack of rate limiting for unauthenticated users, making it particularly dangerous because it can be executed by anyone with access to the network. Organizations running affected ircd implementations should immediately implement rate limiting for unregistered users, update to patched versions of the software, and consider implementing additional network-level controls to prevent such attacks from overwhelming server resources.
This vulnerability demonstrates the critical importance of implementing proper access controls and resource management even for unauthenticated users in network services. The lack of rate limiting for anonymous connections creates an exploitable condition that can be leveraged by attackers to consume server resources and disrupt legitimate service delivery. The attack vector is particularly concerning because it requires no authentication credentials and can be executed remotely, making it an attractive target for malicious actors seeking to disrupt irc communications. The slow dequeuing mechanism adds to the severity by ensuring that the resource exhaustion occurs gradually but persistently, making detection and mitigation more challenging for system administrators.