CVE-2007-3679 in Access Gateway
Summary
by MITRE
The Citrix EPA ActiveX control (aka the "endpoint checking control" or CCAOControl Object) before 4.5.0.0 in npCtxCAO.dll in Citrix Access Gateway Standard Edition before 4.5.5 and Advanced Edition before 4.5 HF1 allows remote attackers to download and execute arbitrary programs onto a client system.
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Analysis
by VulDB Data Team • 07/23/2019
The vulnerability described in CVE-2007-3679 represents a critical security flaw in the Citrix Access Gateway Standard and Advanced Edition products that affects versions prior to 4.5.5 and 4.5 HF1 respectively. This vulnerability specifically targets the Citrix EPA ActiveX control, also known as the endpoint checking control or CCAOControl Object, which is implemented through the npCtxCAO.dll library. The flaw resides in how the ActiveX control handles client-side operations, creating an exploitable condition that allows remote attackers to execute arbitrary code on vulnerable systems. The vulnerability is particularly concerning because it operates at the client-side execution layer, enabling attackers to bypass traditional network-level security measures and directly compromise endpoint devices.
The technical implementation of this vulnerability stems from improper validation and handling of input parameters within the Citrix EPA ActiveX control. When the control processes certain client-side requests, it fails to properly sanitize or validate the data being passed to the system, creating an opportunity for malicious code injection. This flaw allows attackers to leverage the ActiveX control's legitimate functionality to download and execute arbitrary programs on the client system without proper authentication or authorization. The vulnerability operates through the ActiveX component's ability to interact with the Windows operating system at a low level, potentially enabling privilege escalation and persistent access to compromised endpoints.
The operational impact of this vulnerability extends beyond simple remote code execution, as it represents a significant threat to enterprise security infrastructure. Organizations using affected Citrix Access Gateway versions face the risk of full system compromise when users interact with malicious web content or exploit the vulnerability through social engineering attacks. The vulnerability affects the core endpoint security checking functionality that Citrix designed to protect corporate networks, creating a paradox where the security mechanism itself becomes a vector for attack. This flaw particularly impacts organizations that rely on Citrix Access Gateway for remote access solutions, as it undermines the trust model that the platform is designed to maintain. The vulnerability can be exploited through various attack vectors including web-based exploits, malicious email attachments, or compromised websites that trigger the vulnerable ActiveX control.
Mitigation strategies for this vulnerability require immediate patching of affected Citrix Access Gateway installations to versions 4.5.5 or 4.5 HF1 respectively, which contain the necessary security fixes. Organizations should also implement network-level controls to restrict access to potentially vulnerable ActiveX components and consider disabling ActiveX controls in web browsers for users who do not require Citrix Access Gateway functionality. The vulnerability aligns with CWE-74 and CWE-94 categories related to code injection and improper input validation, and it maps to ATT&CK techniques involving execution through ActiveX and remote code execution. Security teams should also monitor for indicators of compromise related to suspicious downloads or executions of unknown programs on client systems and implement comprehensive endpoint detection and response measures to identify potential exploitation attempts.