CVE-2009-0521 in Flash Player For Linux
Summary
by MITRE
Untrusted search path vulnerability in Adobe Flash Player 9.x before 9.0.159.0 and 10.x before 10.0.22.87 on Linux allows local users to obtain sensitive information or gain privileges via a crafted library in a directory contained in the RPATH.
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Analysis
by VulDB Data Team • 08/28/2019
The vulnerability identified as CVE-2009-0521 represents a critical untrusted search path issue affecting Adobe Flash Player versions prior to 9.0.159.0 and 10.0.22.87 on Linux systems. This flaw resides in the application's handling of dynamic library loading mechanisms, specifically within the RPATH (runtime search path) configuration that determines where the system looks for shared libraries during program execution. The vulnerability is classified under CWE-427 Untrusted Search Path, which occurs when applications search for libraries in directories that can be manipulated by unprivileged users, creating potential attack vectors for privilege escalation and information disclosure.
The technical exploitation of this vulnerability occurs when a local attacker places a malicious shared library in a directory that appears earlier in the RPATH than the legitimate system libraries. When Adobe Flash Player attempts to load a required library, it inadvertently loads the attacker-controlled version instead of the legitimate system library, potentially executing arbitrary code with the privileges of the Flash Player process. This behavior stems from improper library resolution logic that does not validate or sanitize the search path components, allowing attackers to manipulate the dynamic loading process through carefully crafted library files placed in directories within the RPATH.
The operational impact of this vulnerability extends beyond simple privilege escalation to include potential information disclosure and system compromise. An attacker with local access can leverage this vulnerability to execute arbitrary code with elevated privileges, potentially leading to full system compromise. The vulnerability affects all Linux installations of affected Flash Player versions, making it particularly dangerous in multi-user environments where local attackers may not have direct access to system resources but can manipulate the RPATH environment. This flaw aligns with ATT&CK technique T1068, which covers privilege escalation through the exploitation of software vulnerabilities, and specifically targets the execution of malicious code through library injection methods.
Mitigation strategies for CVE-2009-0521 primarily involve immediate patching of affected Adobe Flash Player installations to versions 9.0.159.0 or 10.0.22.87 and later, which address the untrusted search path issue through proper library loading mechanisms. System administrators should also implement strict library path controls by removing unnecessary directories from RPATH, using absolute paths for library loading, and implementing proper privilege separation between user processes and system libraries. Additional protective measures include monitoring for unauthorized library modifications in system directories, implementing file integrity monitoring solutions, and considering the complete removal of Flash Player from systems where it is not essential for critical operations. Organizations should also conduct regular security assessments to identify other applications with similar untrusted search path vulnerabilities and ensure proper sandboxing of potentially vulnerable components to limit the impact of such flaws.