CVE-2005-3267 in Skype
Summary
by MITRE
Integer overflow in Skype client before 1.4.x.84 on Windows, before 1.3.x.17 on Mac OS, before 1.2.x.18 on Linux, and 1.1.x.6 and earlier allows remote attackers to cause a denial of service (crash) via crafted network data with a large Object Counter value, which leads to a resultant heap-based buffer overflow.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 11/22/2024
The vulnerability described in CVE-2005-3267 represents a critical integer overflow flaw affecting multiple platforms of the Skype client software. This issue specifically impacts Skype versions prior to 1.4.x.84 on Windows, 1.3.x.17 on Mac OS, 1.2.x.18 on Linux, and versions 1.1.x.6 and earlier on all platforms. The vulnerability stems from insufficient input validation within the network protocol handling mechanism, where the client fails to properly validate the Object Counter value contained in incoming network packets. When an attacker crafts malicious network data with an excessively large Object Counter value, the application processes this data without adequate boundary checking, leading to a predictable arithmetic overflow condition.
The technical execution of this vulnerability involves a heap-based buffer overflow that occurs when the Skype client attempts to allocate memory based on the malformed Object Counter value. This integer overflow results in the calculation of an incorrect buffer size, causing the application to allocate insufficient memory for the intended data structure. When subsequent data is written to this improperly sized buffer, it overflows into adjacent memory regions, corrupting heap metadata and potentially leading to arbitrary code execution or application crash. The vulnerability is classified as a heap-based buffer overflow, which falls under the Common Weakness Enumeration category CWE-121, and represents a specific instance of CWE-129, where insufficient validation of the length parameter leads to buffer overflows.
From an operational perspective, this vulnerability presents a significant risk for remote attackers seeking to disrupt Skype services or compromise client systems. The denial of service impact is immediate and predictable, as the application crashes upon processing the malformed network data, rendering the client unavailable to legitimate users. However, the potential for more severe exploitation exists, particularly in environments where Skype clients might be running with elevated privileges or where the heap corruption could be leveraged to achieve code execution. The vulnerability affects the core communication functionality of Skype, making it particularly attractive to threat actors targeting enterprise communication infrastructure.
The mitigation strategy for CVE-2005-3267 requires immediate deployment of vendor patches and updates to the affected Skype client versions. System administrators should prioritize updating to the latest stable versions of Skype that contain fixes for this integer overflow vulnerability. Network segmentation and monitoring should be implemented to detect and block suspicious network traffic patterns that might indicate exploitation attempts. Additionally, implementing intrusion detection systems with signature-based detection for known malicious network data patterns can help prevent exploitation. The vulnerability aligns with ATT&CK technique T1203, which covers exploitation of remote services, and demonstrates the importance of input validation as outlined in the MITRE ATT&CK framework for preventing such classes of vulnerabilities. Organizations should also consider implementing application whitelisting policies to restrict execution of unauthorized Skype versions and conduct regular vulnerability assessments to identify similar integer overflow conditions in other networked applications.