CVE-2005-0340 in Mac OS X
Summary
by MITRE
Integer signedness error in Apple File Service (AFP Server) allows remote attackers to cause a denial of service (application crash) via a negative UAM string length in a FPLoginExt packet.
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Analysis
by VulDB Data Team • 02/08/2025
The vulnerability identified as CVE-2005-0340 represents a critical integer signedness error within Apple File Service AFP Server implementation that exposes systems to remote denial of service attacks. This flaw specifically manifests when processing FPLoginExt packets containing negative UAM string lengths, creating a scenario where the server fails to properly validate input parameters before processing them. The issue stems from improper handling of signed versus unsigned integer values during network packet interpretation, which is a common class of programming error that can lead to unpredictable behavior and system instability.
The technical exploitation of this vulnerability occurs through the manipulation of network traffic sent to AFP servers, where attackers craft malicious FPLoginExt packets with intentionally negative UAM string length values. When the AFP server processes these malformed packets, the signedness error causes the application to interpret the negative value incorrectly, leading to buffer overflows or memory corruption conditions that ultimately result in application crashes. This type of vulnerability falls under CWE-190, Integer Overflow or Wraparound, and specifically relates to CWE-191, Integer Underflow, as the negative values cause unexpected behavior in integer arithmetic operations. The vulnerability demonstrates poor input validation practices and highlights the importance of proper boundary checking in network service implementations.
From an operational impact perspective, this vulnerability creates significant security risks for organizations relying on Apple File Service for file sharing and network access. The denial of service condition affects availability of critical file services, potentially disrupting business operations and user access to shared resources. Attackers can exploit this vulnerability without authentication requirements, making it particularly dangerous as it can be triggered remotely by any network entity capable of sending crafted packets to the affected AFP server. The vulnerability also represents a potential entry point for more sophisticated attacks, as the application instability could provide opportunities for further exploitation or information disclosure. Organizations running AFP services are particularly vulnerable since this flaw affects the core file sharing functionality that many enterprises depend upon for internal collaboration and data management.
The recommended mitigations for this vulnerability involve immediate application of vendor patches and updates to AFP Server implementations to address the integer signedness error. Network administrators should implement proper input validation at network boundaries to filter out malformed FPLoginExt packets before they reach the AFP server. Additionally, implementing network segmentation and access controls can help limit the exposure of AFP services to untrusted networks. Security monitoring should include detection of unusual network traffic patterns that might indicate exploitation attempts. The remediation process should also involve comprehensive testing of patched systems to ensure that the fix does not introduce compatibility issues with existing AFP clients or services. Organizations should consider implementing intrusion detection systems capable of identifying and alerting on suspicious AFP packet structures that match the vulnerability characteristics. This vulnerability demonstrates the critical importance of proper integer handling in network services and aligns with ATT&CK technique T1499.004, Endpoint Denial of Service, as it specifically targets service availability through application-level exploitation.