CVE-2000-1102 in IRCD
Summary
by MITRE
PTlink IRCD 3.5.3 and PTlink Services 1.8.1 allow remote attackers to cause a denial of service (server crash) via "mode +owgscfxeb" and "oper" commands.
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Analysis
by VulDB Data Team • 05/28/2018
The vulnerability identified as CVE-2000-1102 affects PTlink IRCD version 3.5.3 and PTlink Services version 1.8.1, representing a critical denial of service weakness that can be exploited by remote attackers to crash the affected IRC servers. This flaw specifically manifests through the manipulation of specific command sequences involving mode changes and operator commands, demonstrating a fundamental flaw in input validation and command processing within the IRC daemon software. The vulnerability operates by exploiting the way the server handles certain combinations of mode flags and operational commands, creating a condition where legitimate server operations can be disrupted through carefully crafted malicious inputs.
The technical execution of this vulnerability involves attackers sending specifically formatted "mode +owgscfxeb" commands followed by "oper" commands to the targeted IRC server. These commands exploit a buffer overflow or memory corruption condition within the PTlink IRCD implementation where the server fails to properly validate or sanitize the input parameters before processing them. The mode command with the specified flags creates a scenario where the server's internal data structures become corrupted or overwritten, leading to an immediate crash of the IRC daemon process. This type of vulnerability falls under CWE-121, which describes stack-based buffer overflow conditions, and represents a classic example of improper input validation in network services. The attack vector is particularly dangerous because it requires no authentication and can be executed from any remote location with network access to the IRC server.
The operational impact of this vulnerability extends beyond simple server downtime, as it can disrupt entire IRC networks that rely on the affected servers for communication and services. When the server crashes, it affects all users connected to that particular IRC network, potentially causing widespread disruption to real-time communication channels, chat rooms, and collaborative workspaces that depend on these services. The vulnerability also has implications for network stability and availability, as administrators may need to restart services and potentially lose connection logs or user sessions. From an attacker perspective, this represents a low-effort, high-impact method for disrupting services, making it attractive for malicious actors seeking to cause disruption. The vulnerability aligns with ATT&CK technique T1499.004, which covers network denial of service attacks, and demonstrates how seemingly minor implementation flaws in network services can have significant operational consequences.
Mitigation strategies for this vulnerability should focus on immediate patching of the affected software versions, as PTlink IRCD 3.5.3 and PTlink Services 1.8.1 were superseded by newer releases that addressed these specific memory handling issues. Network administrators should implement strict input validation measures and consider deploying intrusion detection systems to monitor for suspicious command sequences. Additionally, implementing rate limiting and access controls on operator commands can help reduce the attack surface. The vulnerability highlights the importance of proper software security testing and the need for robust input validation in network services, particularly those handling user-provided commands. Organizations should also maintain updated security patches and regularly review their network service configurations to prevent similar issues from occurring in other software components. The incident serves as a reminder of the critical importance of secure coding practices and the potential for remote code execution vulnerabilities to be exploited for denial of service attacks in network infrastructure services.