CVE-2002-1675 in IRCd
Summary
by MITRE
Format string vulnerability in the Cio_PrintF function of cio_main.c in Unreal IRCd 3.1.1 allows remote attackers to cause a denial of service (crash) and possibly execute arbitrary code via format string specifiers.
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Analysis
by VulDB Data Team • 06/09/2018
The CVE-2002-1675 vulnerability represents a critical format string flaw in the Unreal IRCd 3.1.1 internet relay chat server implementation. This vulnerability specifically affects the Cio_PrintF function within the cio_main.c source file, which handles formatted output operations for the IRC daemon. The flaw arises from improper handling of user-supplied input data that gets directly processed through format string functions without adequate sanitization or validation. Attackers can exploit this weakness by sending specially crafted messages or commands containing format string specifiers to the IRC server, triggering unpredictable behavior in the application's memory management and execution flow.
The technical exploitation of this vulnerability leverages the fundamental design flaw in how the IRC daemon processes formatted output requests. When the Cio_PrintF function receives input data that contains format specifiers such as %s, %d, or %x, the application fails to properly escape or validate these characters before passing them to underlying printf-family functions. This creates a scenario where attacker-controlled data can manipulate the format string parsing mechanism, potentially leading to stack corruption, memory access violations, or code execution. The vulnerability operates at the core level of the IRC daemon's communication handling, making it particularly dangerous as it can be triggered through normal IRC protocol interactions.
The operational impact of this vulnerability extends beyond simple denial of service conditions to potentially enable remote code execution on vulnerable systems. When exploited successfully, the format string vulnerability can cause the IRC daemon to crash and restart repeatedly, resulting in persistent denial of service for legitimate users. More critically, skilled attackers can craft payloads that overwrite critical memory locations, inject malicious code, or manipulate program execution flow to gain unauthorized access to the compromised system. This makes the vulnerability particularly attractive to threat actors seeking to establish persistent access to IRC networks or to disrupt services within the IRC ecosystem. The vulnerability affects systems running Unreal IRCd 3.1.1 and potentially other versions that share similar implementation flaws, creating widespread exposure across IRC infrastructure.
Security mitigations for CVE-2002-1675 require immediate patching of the Unreal IRCd software to address the format string handling issue in the Cio_PrintF function. System administrators should implement input validation and sanitization measures that prevent format specifiers from being processed directly through printf functions without proper escaping. Network segmentation and access controls should be enforced to limit exposure of IRC services to untrusted networks, while monitoring systems should be deployed to detect suspicious protocol interactions that may indicate exploitation attempts. Organizations should also consider implementing intrusion detection systems that can identify patterns associated with format string exploitation attempts. This vulnerability aligns with CWE-134, which specifically addresses the use of format strings inappropriately, and maps to ATT&CK technique T1059.007 for command and scripting interpreter, as exploitation may involve executing arbitrary code through compromised IRC infrastructure. The vulnerability demonstrates the critical importance of proper input validation and the dangers of insecure coding practices in network services, particularly those handling user-provided data through format string operations.