CVE-2018-10722 in CylancePROTECT
Summary
by MITRE
In Cylance CylancePROTECT before 1470, an unprivileged local user can obtain SYSTEM privileges because users have Modify access to the %PROGRAMFILES%\Cylance\Desktop\log folder, the CyUpdate process grants users Modify access to new files created in this folder, and a new file can be a symlink chain to a pathname of an arbitrary DLL that CyUpdate uses.
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Analysis
by VulDB Data Team • 02/02/2020
This vulnerability exists within Cylance CylancePROTECT software version 1470 and earlier, representing a critical privilege escalation flaw that allows unprivileged local users to gain SYSTEM-level access on affected systems. The vulnerability stems from improper access control mechanisms within the software's logging infrastructure, specifically targeting the %PROGRAMFILES%\Cylance\Desktop\log folder which is accessible to standard users with modify permissions. The core technical flaw involves the CyUpdate process which dynamically grants modify access to newly created files within this log directory, creating a window of opportunity for malicious exploitation.
The operational impact of this vulnerability is severe as it enables a low-privilege attacker to manipulate the software's update process through symbolic link manipulation. When the CyUpdate process encounters a new file in the log directory, it processes this file as part of its normal operation, potentially loading malicious DLLs that have been strategically placed through the symlink chain. This creates a sophisticated attack vector where an attacker can plant a malicious DLL at an arbitrary location on the filesystem and have it executed with SYSTEM privileges by the CyUpdate process. The vulnerability aligns with CWE-276, which describes improper privileges, and demonstrates how inadequate access control can lead to privilege escalation.
The attack chain requires an attacker to first establish a symbolic link within the log directory that points to a target DLL location, then trigger the CyUpdate process to process this malicious file. This exploitation technique leverages the principle of least privilege violation and demonstrates how legitimate software processes can be abused to execute arbitrary code with elevated privileges. The vulnerability affects systems where CylancePROTECT is installed and represents a significant risk to enterprise environments where this security solution is deployed, as it provides a persistent backdoor mechanism for attackers to escalate their privileges.
Mitigation strategies should focus on immediate access control remediation, including restricting user modify permissions on the Cylance log directory and implementing proper file system permissions for the CyUpdate process. Organizations should also consider implementing application whitelisting policies to prevent unauthorized DLL loading, and apply the vendor-provided patch for CylancePROTECT version 1470 or later. From an ATT&CK perspective, this vulnerability maps to privilege escalation techniques using trusted process and file system manipulation, making it particularly dangerous in environments where security monitoring is not properly configured to detect such anomalous file system behaviors.