CVE-2025-5129 is a critical vulnerability identified in Sangfor's Zero Trust Access Control System aTrust version 2.3.10.60. The flaw resides in an unspecified functionality within the MSASN1.dll library, which is part of the product's software stack. The vulnerability is characterized as an uncontrolled search path issue, meaning that the software improperly handles the locations it searches for DLLs or other resources, potentially allowing an attacker to influence which code is loaded and executed. Exploitation requires local access to the affected system and a high level of attack complexity, indicating that the attacker must have some privileges and technical skill to leverage the flaw. The vulnerability does not require user interaction or authentication beyond local access, but the attack complexity and required privileges limit the attack surface somewhat. The CVSS 4.0 base score is 7.3 (high severity), reflecting significant impact on confidentiality, integrity, and availability if exploited. The vendor has been notified but has not responded or issued a patch, and while no known exploits are currently active in the wild, public disclosure of the exploit code increases the risk of future attacks. The uncontrolled search path vulnerability could allow an attacker to execute arbitrary code or escalate privileges by tricking the system into loading malicious DLLs, potentially compromising the entire access control system and the protected network environment.

For European organizations using Sangfor's aTrust 2.3.10.60, this vulnerability poses a significant risk to network security and access control integrity. Since aTrust is a zero trust access control system, it is likely deployed in environments requiring strict authentication and authorization controls, such as government agencies, financial institutions, and critical infrastructure operators. Exploitation could lead to unauthorized code execution, privilege escalation, and potential full compromise of the access control system, undermining the zero trust security model. This could result in unauthorized access to sensitive data, disruption of secure remote access, and lateral movement within corporate networks. The local access requirement somewhat limits remote exploitation, but insider threats or attackers who have gained initial footholds could leverage this vulnerability to deepen their control. The lack of vendor response and patch availability increases the urgency for organizations to implement compensating controls. Given the critical role of access control systems, exploitation could have cascading effects on confidentiality, integrity, and availability of enterprise resources.

1. Immediate mitigation should focus on restricting local access to systems running Sangfor aTrust 2.3.10.60, ensuring only trusted administrators have physical or remote desktop access. 2. Employ application whitelisting and strict DLL loading policies to prevent unauthorized DLLs from being loaded by the MSASN1.dll library or related processes. 3. Monitor system logs and behavior for unusual DLL load attempts or privilege escalation activities. 4. Isolate the affected systems within segmented network zones to limit lateral movement if compromise occurs. 5. Engage with Sangfor support channels persistently to obtain official patches or guidance. 6. Consider deploying endpoint detection and response (EDR) solutions capable of detecting anomalous DLL injection or code execution patterns. 7. If feasible, upgrade or replace the affected product with a version or alternative solution that does not contain this vulnerability. 8. Conduct regular security audits and penetration tests focusing on local privilege escalation vectors to identify and remediate similar risks.