CVE-2007-6535 in Toolbar
Summary
by MITRE
Buffer overflow in the YShortcut ActiveX control in YShortcut.dll 2006.8.15.1 in Yahoo! Toolbar might allow attackers to execute arbitrary code via a long string to the IsTaggedBM method.
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Analysis
by VulDB Data Team • 07/30/2021
The vulnerability identified as CVE-2007-6535 represents a critical buffer overflow flaw within the YShortcut ActiveX control component of Yahoo! Toolbar version 2006.8.15.1. This particular vulnerability exists within the YShortcut.dll dynamic link library and specifically affects the IsTaggedBM method which handles user input without proper bounds checking. The flaw stems from inadequate input validation mechanisms that fail to enforce size limitations on string parameters passed to the method, creating an exploitable condition where maliciously crafted input can overwrite adjacent memory locations.
The technical implementation of this buffer overflow occurs when the IsTaggedBM method processes user-supplied strings without validating their length against the allocated buffer space. This allows an attacker to provide an excessively long string that exceeds the predetermined buffer capacity, resulting in memory corruption that can be leveraged to execute arbitrary code with the privileges of the affected application. The vulnerability is particularly dangerous because it operates within the context of a widely distributed ActiveX control that is automatically installed with Yahoo! Toolbar, making it accessible to a large user base. The flaw aligns with CWE-121, which describes stack-based buffer overflow conditions where insufficient bounds checking permits memory corruption.
The operational impact of this vulnerability extends beyond simple code execution as it provides attackers with potential persistence mechanisms and privilege escalation opportunities within the victim's system. Since ActiveX controls run with the security context of the user, successful exploitation could allow attackers to install malware, modify system files, or establish backdoors. The vulnerability also demonstrates characteristics consistent with ATT&CK technique T1195.002, which involves the exploitation of ActiveX components for malicious code delivery and execution. The widespread deployment of Yahoo! Toolbar across various Windows systems created a significant attack surface that could be exploited at scale, particularly in enterprise environments where the toolbar was commonly installed.
Mitigation strategies for this vulnerability should focus on immediate remediation through software updates and patches provided by Yahoo! as well as network-level defenses including browser security settings that restrict ActiveX control execution. Organizations should implement security awareness training to educate users about the risks of installing untrusted software components and consider disabling ActiveX controls in web browsers where possible. The vulnerability highlights the importance of proper input validation and bounds checking in component-based software architectures, emphasizing the need for secure coding practices that prevent buffer overflow conditions. Additionally, regular security assessments of installed software components and ActiveX controls should be conducted to identify and remediate similar vulnerabilities that may exist in other third-party applications.