CVE-2011-2729 in Tomcat
Summary
by MITRE
native/unix/native/jsvc-unix.c in jsvc in the Daemon component 1.0.3 through 1.0.6 in Apache Commons, as used in Apache Tomcat 5.5.32 through 5.5.33, 6.0.30 through 6.0.32, and 7.0.x before 7.0.20 on Linux, does not drop capabilities, which allows remote attackers to bypass read permissions for files via a request to an application.
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Analysis
by VulDB Data Team • 11/18/2021
The vulnerability identified as CVE-2011-2729 resides within the jsvc daemon component of Apache Commons, specifically in the native unix implementation where the jserv-unix.c file fails to properly drop system capabilities during process initialization. This flaw affects Apache Tomcat versions ranging from 5.5.32 through 5.5.33, 6.0.30 through 6.0.32, and 7.0.x versions prior to 7.0.20 on Linux systems. The core issue manifests when the daemon process starts with elevated privileges and retains certain Linux capabilities that should be dropped for security purposes.
The technical implementation flaw stems from the improper handling of Linux capabilities within the daemon startup process. When jsvc initializes the daemon process, it fails to invoke the appropriate capability dropping mechanisms that would normally strip away unnecessary privileges from the running process. This allows the daemon to maintain capabilities such as CAP_DAC_READ_SEARCH which enables bypassing file read permission checks. The vulnerability operates at the system call level where the process retains the ability to access files that would normally be restricted based on standard file permissions.
From an operational standpoint, this vulnerability creates a significant security risk for web applications running on affected Apache Tomcat versions. Remote attackers can exploit this weakness to gain unauthorized access to files that should be protected by standard read permissions. The impact extends beyond simple file access as it enables attackers to potentially read sensitive configuration files, application data, or other restricted resources that could contain authentication credentials, database connection strings, or business-critical information. The vulnerability essentially undermines the principle of least privilege that should govern process execution in secure environments.
The security implications align with CWE-250, which addresses execution of code with unnecessary privileges, and represents a clear violation of the principle that processes should run with the minimal set of capabilities required for their operation. From an ATT&CK framework perspective, this vulnerability maps to T1068, which covers 'Exploitation for Privilege Escalation', and T1566, covering 'Phishing', as attackers may use this to gather information that could facilitate further attacks. The vulnerability also relates to T1078, which covers 'Valid Accounts', since the attacker can access files that would normally require specific account privileges to read.
Mitigation strategies should focus on immediate patching of affected Apache Tomcat versions to the latest releases that address this capability dropping issue. Organizations should also implement proper capability management policies and regularly audit running processes to ensure that unnecessary capabilities are not retained. System administrators should consider implementing additional monitoring for suspicious file access patterns and ensure that all system components are updated to versions that properly handle Linux capabilities. The fix involves ensuring that the jsvc daemon properly calls the appropriate capability dropping functions before the daemon process assumes its operational role, thereby preventing the retention of unnecessary privileges that could be exploited by attackers.