CVE-2004-0043 in Yahoo!
Summary
by MITRE
Buffer overflow in Yahoo Instant Messenger 5.6.0.1351 and earlier allows remote attackers to cause a denial of service (crash) and possibly execute arbitrary code via a long filename in the download feature.
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Analysis
by VulDB Data Team • 03/09/2021
The vulnerability identified as CVE-2004-0043 represents a critical buffer overflow flaw within Yahoo Instant Messenger version 5.6.0.1351 and earlier implementations. This security weakness resides in the application's handling of file downloads, specifically when processing filenames that exceed predetermined buffer limits. The flaw stems from inadequate input validation mechanisms that fail to properly sanitize or truncate excessively long filename strings before processing them within the application's memory structures. The vulnerability operates at the application layer and demonstrates characteristics consistent with CWE-121, which describes stack-based buffer overflow conditions where insufficient bounds checking allows attackers to overwrite adjacent memory locations. The technical implementation involves the client-side application receiving a maliciously crafted filename through the download feature, which then gets stored in a fixed-size buffer without proper length verification, leading to memory corruption.
The operational impact of this vulnerability extends beyond simple denial of service conditions to potentially enable remote code execution capabilities. When an attacker crafts a specially formatted filename that exceeds the allocated buffer space, the overflow can overwrite critical program memory segments including return addresses and function pointers. This memory corruption can lead to unpredictable application behavior, resulting in crashes and system instability. However, the more severe implications arise from the possibility of arbitrary code execution, where carefully crafted overflow data can redirect program execution to malicious code injected into the compromised memory space. The vulnerability affects users who are actively engaged in file sharing activities through the instant messaging platform, making it particularly dangerous in environments where users frequently accept file transfers from unknown or untrusted sources. The attack vector requires minimal user interaction, as the vulnerability can be triggered through automated file transfer mechanisms, making it especially concerning for widespread exploitation.
Mitigation strategies for CVE-2004-0043 should focus on immediate patching and application updates to address the underlying buffer overflow condition. System administrators should prioritize updating Yahoo Instant Messenger to versions that include proper input validation and bounds checking mechanisms. The implementation of network-level protections such as firewalls and intrusion detection systems can help monitor and filter suspicious file transfer activities. Additionally, user education regarding the dangers of accepting files from untrusted sources remains critical in reducing exploitation risk. Security configurations should enforce strict filename validation rules that limit the maximum length of accepted filenames and implement proper error handling for oversized inputs. Organizations should consider implementing application whitelisting policies that restrict the execution of vulnerable instant messaging applications until proper security patches have been deployed. The vulnerability's characteristics align with ATT&CK technique T1203, which covers exploitation of remote services through buffer overflow conditions, emphasizing the need for comprehensive defensive measures that address both the immediate security flaw and broader system hardening practices. Regular security assessments and vulnerability scanning should be conducted to identify similar buffer overflow conditions in other legacy applications that may be susceptible to similar exploitation techniques.