CVE-2014-2956 in Secure Search toolbar
Summary
by MITRE
ScriptHelperApi in the AVG ScriptHelper ActiveX control in ScriptHelper.exe in AVG Secure Search toolbar before 18.1.7.598 and AVG Safeguard before 18.1.7.644 does not implement domain-based access control for method calls, which allows remote attackers to trigger the downloading and execution of arbitrary programs via a crafted web site.
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Analysis
by VulDB Data Team • 08/21/2024
The CVE-2014-2956 vulnerability represents a critical security flaw in the AVG Secure Search toolbar and AVG Safeguard software products, specifically within the ScriptHelper ActiveX control component. This vulnerability exists in versions prior to 18.1.7.598 for the toolbar and 18.1.7.644 for the safeguard product, creating a dangerous attack surface that enables remote code execution through web-based exploitation. The flaw stems from improper implementation of domain-based access control mechanisms within the ScriptHelperApi functionality, which should have restricted method calls based on the originating domain but failed to enforce such restrictions effectively.
The technical implementation of this vulnerability involves the ScriptHelper ActiveX control running with elevated privileges in the context of the user's browser session, yet lacking proper security boundaries that would normally prevent cross-domain method invocation. This absence of domain-based access control allows malicious web pages to directly call methods within the ActiveX control without proper authorization checks, effectively bypassing the security model that should isolate potentially dangerous operations from untrusted web content. The vulnerability specifically affects the ScriptHelper.exe process which operates as a system-level component, making the attack vector particularly dangerous as it can leverage the elevated privileges of the running process to execute arbitrary code on the target system.
The operational impact of this vulnerability extends beyond simple remote code execution, as it enables attackers to install malicious software without user interaction or explicit consent, effectively creating a backdoor for persistent access. Attackers can craft malicious websites that automatically download and execute arbitrary programs, including malware, trojans, or additional exploit payloads, leveraging the trusted ActiveX control to bypass traditional security measures such as antivirus detection and user permission prompts. This vulnerability aligns with ATT&CK technique T1190 for Exploit Public-Facing Application and T1059 for Command and Scripting Interpreter, as it allows for the execution of arbitrary code through web-based attack vectors. The lack of domain-based access control creates a persistent threat vector that can be exploited across multiple sessions and potentially affect numerous users who have the vulnerable AVG software installed, making it particularly attractive to threat actors seeking scalable compromise capabilities.
Security mitigations for this vulnerability require immediate patching of affected software versions to implement proper domain-based access control mechanisms within the ScriptHelper ActiveX control. Organizations should also consider disabling ActiveX controls in browser environments where possible, implementing strict browser security policies, and conducting comprehensive vulnerability assessments to identify other potentially affected components. The remediation process should include verification that the updated ScriptHelper.exe process properly enforces domain restrictions and that no legacy ActiveX controls remain in the system. This vulnerability demonstrates the critical importance of proper access control implementation in privileged system components and highlights how insufficient security boundaries in trusted software can create significant risk for entire user populations. The issue also relates to CWE-284 Access Control, which specifically addresses improper access control mechanisms, and represents a classic example of how missing security controls in system-level components can enable arbitrary code execution with elevated privileges.