CVE-2015-5290 in ircd-ratbox
Summary
by MITRE • 01/25/2023
ircd-ratbox 3.0.9 mishandles the MONITOR command which allows remote attackers to cause a denial of service (system out-of-memory event).
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Analysis
by VulDB Data Team • 03/17/2024
The vulnerability identified as CVE-2015-5290 affects ircd-ratbox version 3.0.9, a widely used Internet Relay Chat server implementation that serves as a foundational component for many IRC networks. This particular flaw manifests within the MONITOR command processing mechanism, which is designed to allow users to track the online status of other users on the network. The MONITOR command functionality enables clients to receive notifications when specified users come online or go offline, serving as a crucial feature for maintaining connectivity awareness within IRC environments. However, the implementation contains a critical flaw that can be exploited by remote attackers to manipulate the server's memory management processes.
The technical exploitation of this vulnerability occurs through malformed or excessively crafted MONITOR command requests that cause the ircd-ratbox server to allocate memory resources without proper bounds checking or validation. When processing these malicious inputs, the server fails to properly handle the memory allocation requests, leading to uncontrolled memory consumption that eventually results in system out-of-memory conditions. This memory exhaustion can cause the server process to crash or become unresponsive, effectively rendering the IRC network unavailable to legitimate users. The flaw specifically resides in the command parsing and memory management logic where the server does not adequately validate the number of monitored users or the length of monitoring requests, allowing attackers to submit requests that trigger continuous memory allocation without proper cleanup mechanisms.
The operational impact of CVE-2015-5290 extends beyond simple service disruption, as it represents a significant threat to IRC network stability and availability. Network administrators who rely on ircd-ratbox servers for their communication infrastructure face potential downtime that can affect thousands of users simultaneously, particularly in large networks where the MONITOR functionality is heavily utilized. The vulnerability can be exploited by any remote attacker with access to the IRC server, making it particularly dangerous as it requires no authentication or privileged access. This allows malicious actors to disrupt network operations at will, potentially causing cascading failures that affect not just the targeted server but also connected networks through the IRC protocol's federated architecture.
This vulnerability aligns with CWE-129, which describes improper validation of array index values, and CWE-400, which covers resource exhaustion vulnerabilities. The flaw demonstrates characteristics consistent with attack patterns found in the MITRE ATT&CK framework under the T1499 category for network denial of service attacks. The memory exhaustion nature of the vulnerability also corresponds to techniques used in resource exhaustion attacks that target system stability and availability. Organizations using ircd-ratbox servers should implement immediate mitigations including updating to patched versions, implementing rate limiting for MONITOR command usage, and configuring memory limits on server processes to prevent complete system crashes. Additionally, network monitoring should be enhanced to detect unusual memory consumption patterns that may indicate exploitation attempts, while proper input validation should be enforced at all command processing levels to prevent similar vulnerabilities from manifesting in other areas of the server implementation.