CVE-2004-2373 in Instant Messenger
Summary
by MITRE
The Buddy icon file for AOL Instant Messenger (AIM) 4.3 through 5.5 is created in a predictable location, which may allow remote attackers to use a shell: URI to exploit other vulnerabilities that involve predictable locations.
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Analysis
by VulDB Data Team • 08/21/2025
The vulnerability described in CVE-2004-2373 represents a significant security flaw in the AOL Instant Messenger client software that affected versions 4.3 through 5.5. This issue stems from the predictable file naming and storage mechanisms used by the AIM client when processing buddy icon files, creating a pathway for remote attackers to exploit other system vulnerabilities through carefully crafted shell: URI references. The vulnerability operates within the broader context of predictable file location attacks that have been documented in various security frameworks including CWE-20, which specifically addresses "Improper Neutralization of Special Elements used in a Command" and CWE-310, which covers "Cryptographic Issues." The predictable nature of the file location creates an attack surface that aligns with ATT&CK technique T1059.007 for "Command and Scripting Interpreter: PowerShell" and T1059.003 for "Command and Scripting Interpreter: Windows Command Shell" when attackers leverage shell: URI constructs to execute malicious payloads.
The technical flaw manifests when AIM processes buddy icon files and stores them in a predetermined directory structure that attackers can easily identify and manipulate. This predictable storage mechanism allows remote adversaries to craft malicious shell: URI references that can trigger the execution of arbitrary code when the system attempts to process these icons. The vulnerability specifically exploits the lack of proper input validation and file path handling within the AIM client, enabling attackers to bypass normal security restrictions that would otherwise prevent unauthorized file access or execution. The shell: URI protocol, when combined with the predictable file location, creates an attack vector that can be leveraged to execute malicious code with the privileges of the user running AIM. This flaw represents a classic case of path traversal vulnerability that has been addressed in various security standards and frameworks including those related to secure file handling practices.
The operational impact of this vulnerability extends beyond simple local privilege escalation, as it enables attackers to potentially compromise entire systems through the exploitation of the AIM client's predictable file storage mechanisms. When combined with other vulnerabilities or attack vectors, this issue can lead to complete system compromise, data theft, or unauthorized access to network resources. The vulnerability affects users who are actively using AIM client software and exposes them to remote code execution attacks that can be initiated without any user interaction beyond receiving a malicious buddy icon file. The attack requires minimal user interaction and can be executed entirely through the AIM communication protocol, making it particularly dangerous in enterprise environments where instant messaging systems are widely deployed. Security professionals should consider this vulnerability as part of a broader attack surface analysis that includes other predictable file location issues and shell injection vulnerabilities commonly found in messaging and communication applications.
Mitigation strategies for this vulnerability should focus on implementing proper input validation and secure file handling practices within the AIM client and similar messaging applications. Organizations should consider disabling the automatic processing of buddy icon files or implementing strict file path validation to prevent the exploitation of predictable storage locations. The recommended approach involves updating to newer versions of AIM that address this specific vulnerability, as well as implementing network-level controls that can detect and block malicious shell: URI references. Security measures should also include user education about the risks of accepting buddy icons from untrusted sources and implementing application whitelisting policies that restrict the execution of potentially malicious shell: URI constructs. Additional protections include configuring operating system security features such as DEP (Data Execution Prevention) and ASLR (Address Space Layout Randomization) to make exploitation more difficult, though these measures provide only partial protection against this specific vulnerability. The remediation process should also include monitoring network traffic for suspicious shell: URI patterns and implementing intrusion detection systems that can identify potential exploitation attempts targeting this vulnerability.