CVE-2004-1892 in eMule
Summary
by MITRE
Stack-based buffer overflow in DecodeBase16 function, as used in the (1) IRC module and (2) web server in eMule 0.42d, allows remote attackers to execute arbitrary code via a long string.
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Analysis
by VulDB Data Team • 07/06/2025
The vulnerability identified as CVE-2004-1892 represents a critical stack-based buffer overflow flaw within the eMule peer-to-peer file sharing application version 0.42d. This vulnerability specifically affects the DecodeBase16 function which is utilized in both the IRC module and the web server component of the software. The flaw stems from inadequate input validation mechanisms that fail to properly check the length of data being processed during base16 decoding operations. When maliciously crafted input exceeds the allocated buffer space, it overflows the stack memory region, potentially allowing attackers to overwrite critical program execution data including return addresses and function pointers.
The technical implementation of this vulnerability demonstrates a classic stack buffer overflow condition where the DecodeBase16 function does not perform sufficient bounds checking on input strings before copying them into fixed-size buffers. This weakness aligns with CWE-121, which categorizes stack-based buffer overflow conditions that occur when insufficient bounds checking is performed on buffer operations. The vulnerability exists in both the IRC module functionality and the embedded web server, indicating a systemic flaw in the application's input handling architecture. Attackers can exploit this by sending specially crafted base16 encoded strings that exceed the buffer capacity, causing the stack to overflow and potentially leading to arbitrary code execution.
The operational impact of this vulnerability is severe as it enables remote code execution without requiring authentication or local access to the system. An attacker can leverage this flaw from any network location to compromise systems running vulnerable versions of eMule, making it particularly dangerous in peer-to-peer networking environments where users often connect to unknown peers. The attack vector is particularly concerning because the vulnerability affects both network communication modules within the application, providing multiple entry points for exploitation. This vulnerability essentially allows attackers to execute malicious code with the privileges of the eMule process, potentially leading to complete system compromise, data theft, or further network infiltration. The widespread use of eMule in file sharing networks amplifies the potential impact of this vulnerability.
Mitigation strategies for CVE-2004-1892 should prioritize immediate patching of affected eMule installations to version 0.43 or later where the buffer overflow has been corrected. Organizations should implement network segmentation and access controls to limit exposure of vulnerable systems to untrusted networks. The fix typically involves implementing proper bounds checking within the DecodeBase16 function to ensure input strings do not exceed buffer capacity before copying operations occur. Additionally, network monitoring should be enhanced to detect suspicious base16 encoded traffic patterns that may indicate exploitation attempts. System administrators should also consider implementing application whitelisting policies and disabling unnecessary network services such as the embedded web server when not required. This vulnerability aligns with ATT&CK technique T1059.007 for command and scripting interpreter, as successful exploitation could enable attackers to execute arbitrary commands on compromised systems. The vulnerability also relates to T1203, where attackers may leverage such flaws to gain unauthorized access and execute malicious payloads within the target environment.