CVE-2005-0199 in ngIRCd
Summary
by MITRE
Integer underflow in the Lists_MakeMask() function in lists.c in ngIRCd before 0.8.2 allows remote attackers to cause a denial of service (application crash) and possibly execute arbitrary code via a long MODE line that causes an incorrect length calculation, which leads to a buffer overflow.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 12/22/2024
The vulnerability identified as CVE-2005-0199 represents a critical integer underflow condition within the ngIRCd IRC server software prior to version 0.8.2. This flaw exists specifically within the Lists_MakeMask() function located in the lists.c source file, demonstrating a classic software security weakness that can be exploited to compromise system integrity. The vulnerability operates through a sophisticated attack vector that leverages malformed MODE command inputs to manipulate memory structures and execute unauthorized code execution.
The technical implementation of this vulnerability stems from improper handling of integer arithmetic within the Lists_MakeMask() function. When processing long MODE lines, the software fails to properly validate input lengths, leading to an integer underflow condition where a negative value is calculated and subsequently used as a buffer size parameter. This integer underflow directly translates into an incorrect length calculation that subsequently triggers a buffer overflow condition. The flaw manifests when the application attempts to allocate memory based on the manipulated length value, causing memory corruption that can be exploited by remote attackers to gain control over the affected system.
From an operational impact perspective, this vulnerability presents a significant threat to IRC server availability and security integrity. The primary consequence is a denial of service condition that causes application crashes, effectively disrupting legitimate user access to the IRC network. However, the more severe implications arise from the potential for arbitrary code execution, which allows attackers to gain unauthorized access to the compromised system. This vulnerability affects the core functionality of ngIRCd, making it a prime target for attackers seeking to establish persistent access to IRC infrastructure. The attack requires minimal privileges and can be executed remotely, making it particularly dangerous in networked environments where IRC servers serve as communication platforms for numerous users.
The vulnerability aligns with CWE-190, which specifically addresses integer overflow and underflow conditions, and demonstrates characteristics consistent with the attack patterns described in the MITRE ATT&CK framework under the T1499 category for network denial of service attacks. The exploitation technique involves crafting malicious MODE commands that trigger the integer underflow, which then cascades into memory corruption and potential code execution. This vulnerability represents a classic example of how seemingly minor input validation flaws can result in catastrophic security consequences, particularly in network services that handle untrusted input from remote users.
Mitigation strategies for this vulnerability require immediate patching of affected ngIRCd installations to version 0.8.2 or later, which contains the necessary fixes to prevent integer underflow conditions. System administrators should implement network segmentation and access controls to limit exposure of IRC services to untrusted networks. Additionally, input validation mechanisms should be strengthened to prevent malformed MODE commands from reaching the vulnerable function, and regular security audits should be conducted to identify similar integer arithmetic flaws in other network services. The fix implemented in version 0.8.2 typically involves proper bounds checking and input validation to ensure that calculated buffer sizes remain within acceptable ranges, preventing the integer underflow that leads to the exploitable condition.