CVE-2017-7690 in Proxifier for Mac
Summary
by MITRE
Proxifier for Mac before 2.19.2, when first run, allows local users to gain privileges by replacing the KLoader binary with a Trojan horse program.
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Analysis
by VulDB Data Team • 01/22/2025
The vulnerability identified as CVE-2017-7690 represents a privilege escalation flaw in Proxifier for Mac versions prior to 2.19.2 that specifically exploits the application's initial execution process. This issue occurs during the first run of the software when the application creates or modifies system components, creating a window of opportunity for local attackers to manipulate the installation process. The vulnerability stems from insufficient validation and security controls during the initial setup phase, allowing malicious actors to substitute legitimate system binaries with malicious counterparts.
The technical implementation of this vulnerability involves the KLoader binary, which serves as a critical component in the application's initialization sequence. During first execution, Proxifier creates or modifies this binary without proper integrity checks or secure file permissions, enabling local users to replace it with a Trojan horse program. This manipulation allows the attacker's malicious code to execute with elevated privileges, effectively bypassing standard user restrictions. The flaw operates at the system-level execution context where the application runs with administrative privileges, making the compromise particularly dangerous as it can escalate to full system control.
From an operational perspective, this vulnerability presents significant risk to macOS environments where Proxifier is deployed, particularly in enterprise settings where network proxy configurations are commonly managed through such tools. The attack vector requires local system access, making it exploitable by users who already have login credentials, but the privilege escalation capability means that even low-privilege accounts can gain administrative control. The impact extends beyond simple local privilege escalation as it can enable attackers to modify system configurations, install additional malware, or establish persistent access points within the network infrastructure.
The vulnerability aligns with CWE-276, which addresses improper file permissions, and represents a classic case of insecure temporary file handling during application installation. It also maps to ATT&CK technique T1068, which covers "Exploitation for Privilege Escalation," and T1548.001, covering "Abuse Elevation Control Mechanism." Organizations should immediately apply the patch released in Proxifier version 2.19.2, which addresses the insecure binary replacement mechanism. Additional mitigations include implementing strict file permission controls, monitoring for unauthorized binary modifications, and employing endpoint detection solutions that can identify suspicious file replacement activities. System administrators should also consider restricting local user access where possible and implementing application whitelisting policies to prevent unauthorized binary execution. The vulnerability demonstrates the critical importance of secure installation processes and proper privilege management during application setup phases, highlighting that security considerations must extend beyond runtime operations to include installation and initialization procedures.