CVE-2017-15358 in Charles Proxy
Summary
by MITRE
Race condition in the Charles Proxy Settings suid binary in Charles Proxy before 4.2.1 allows local users to gain privileges via vectors involving the --self-repair option.
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Analysis
by VulDB Data Team • 06/22/2024
The vulnerability identified as CVE-2017-15358 represents a critical race condition flaw within the Charles Proxy software ecosystem, specifically affecting versions prior to 4.2.1. This issue manifests in the Settings suid binary component of Charles Proxy, which operates with elevated privileges through the setuid bit mechanism. The race condition occurs during the execution of the --self-repair option, creating a window of opportunity for local attackers to exploit the system's privilege escalation mechanisms. The fundamental nature of this vulnerability stems from improper synchronization and validation of file operations that occur during the repair process, allowing malicious actors to manipulate system state before privilege escalation occurs.
The technical implementation of this vulnerability involves a classic race condition scenario where the suid binary performs file operations without adequate atomicity guarantees. When the --self-repair option is invoked, the system attempts to restore configuration files or settings while maintaining elevated privileges. However, the timing window between file checks and actual modifications allows local users to substitute or manipulate files in a way that can lead to privilege escalation. This flaw aligns with CWE-362, which specifically addresses race conditions in concurrent programming contexts where the order of operations can be exploited by attackers to gain unauthorized access or elevated privileges. The suid binary's behavior creates a scenario where an attacker can manipulate the environment before the privileged operation executes, effectively hijacking the repair process.
From an operational perspective, this vulnerability poses significant risks to systems running vulnerable versions of Charles Proxy, particularly in environments where multiple users have access to the system. The local privilege escalation capability means that any user with access to the proxy software can potentially elevate their privileges to root level, compromising the entire system. Attackers can leverage this vulnerability to establish persistent access, escalate their privileges to gain full system control, and potentially access sensitive data or systems that should be protected from unauthorized access. The impact extends beyond immediate privilege escalation, as the attacker can then modify system files, install malicious software, or establish backdoors that persist across system reboots. This vulnerability directly maps to ATT&CK technique T1068, which covers privilege escalation through local exploitation of software vulnerabilities.
The mitigation strategies for CVE-2017-15358 primarily focus on upgrading to Charles Proxy version 4.2.1 or later, which contains the necessary patches to address the race condition. Organizations should implement immediate patch management procedures to ensure all systems running Charles Proxy are updated to the secure version. Additionally, system administrators should review and restrict access to the Charles Proxy software, particularly the suid binary components, to minimize the attack surface. The recommended approach includes disabling unnecessary features such as the --self-repair option when not actively needed, implementing proper file permission controls, and conducting regular security audits of the proxy configuration. Organizations should also consider implementing monitoring solutions to detect unauthorized access attempts or privilege escalation activities that may indicate exploitation of this vulnerability, thereby providing an additional layer of defense against potential attackers who might attempt to leverage this race condition for unauthorized system access.