CVE-2011-3640 in Chrome
Summary
by MITRE
** DISPUTED ** Untrusted search path vulnerability in Mozilla Network Security Services (NSS), as used in Google Chrome before 17 on Windows and Mac OS X, might allow local users to gain privileges via a Trojan horse pkcs11.txt file in a top-level directory. NOTE: the vendor s response was "Strange behavior, but we re not treating this as a security bug."
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Analysis
by VulDB Data Team • 08/07/2024
The vulnerability identified as CVE-2011-3640 represents a disputed untrusted search path issue within Mozilla Network Security Services that affected Google Chrome versions prior to 17 on Windows and Mac OS X operating systems. This classification as disputed stems from the vendor's response indicating that while the behavior was unusual, it did not constitute a security bug according to their assessment. The flaw specifically relates to how the system handles cryptographic module loading through the pkcs11.txt configuration file which is used for specifying the location of PKCS#11 cryptographic modules.
The technical implementation of this vulnerability exploits the trust model inherent in the NSS library's module resolution process. When Chrome initializes its cryptographic subsystem, it searches for pkcs11.txt files in various directories including top-level directories where users might place malicious files. This search path behavior creates an opportunity for local attackers to place a specially crafted pkcs11.txt file that points to a malicious cryptographic module, potentially allowing privilege escalation or code execution. The vulnerability operates under CWE-427 Uncontrolled Search Path Element which specifically addresses the risk of malicious code execution through improper handling of search paths.
From an operational perspective, this vulnerability presents a significant risk to systems where local users have access to the file system. Attackers could leverage this weakness by placing a malicious pkcs11.txt file in a directory that gets searched before legitimate cryptographic modules, effectively redirecting the system to load unauthorized cryptographic libraries. The privilege escalation potential stems from the fact that these cryptographic operations often run with elevated privileges, making successful exploitation potentially devastating for system security. This weakness aligns with ATT&CK technique T1068 Exploitation for Privilege Escalation, where adversaries exploit software vulnerabilities to gain higher-level permissions.
The mitigation strategies for this vulnerability primarily involve updating to versions of Chrome that address the search path handling, specifically Chrome 17 and later versions which incorporated proper path validation. Additionally, system administrators should implement strict file permissions and monitoring of critical directories where cryptographic modules are loaded. The recommended approach includes disabling automatic module loading from user-writable directories and implementing whitelisting mechanisms for cryptographic modules. Organizations should also consider deploying endpoint protection solutions that can detect and prevent the placement of malicious configuration files in system directories. The vulnerability highlights the importance of secure coding practices and proper input validation in cryptographic libraries, emphasizing the need for defense-in-depth strategies that go beyond traditional perimeter security measures.