CVE-2010-5209 in Nuance
Summary
by MITRE
Multiple untrusted search path vulnerabilities in Nuance PDF Reader 6.0 allow local users to gain privileges via a Trojan horse (1) dwmapi.dll or (2) exceptiondumpdll.dll file in the current working directory, as demonstrated by a directory that contains a .pdf file. NOTE: some of these details are obtained from third party information.
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Analysis
by VulDB Data Team • 01/30/2018
The vulnerability described in CVE-2010-5209 represents a critical privilege escalation issue within Nuance PDF Reader version 6.0, specifically targeting the application's dynamic link library loading mechanism. This flaw resides in the software's failure to properly validate library paths during dynamic loading operations, creating an exploitable condition where malicious actors can execute arbitrary code with elevated privileges. The vulnerability manifests when the application searches for required system libraries in the current working directory before checking system directories, a common pattern that has been documented in numerous security advisories and exploited in various attack scenarios. The issue directly relates to CWE-426, which describes the insecure loading of dynamic libraries, and aligns with ATT&CK technique T1068, which covers privilege escalation through malicious DLL injection.
The technical implementation of this vulnerability exploits the order of library search paths in Windows operating systems, where applications typically check the current working directory before examining system directories such as system32 or syswow64. When a user opens a PDF file from a directory containing malicious versions of dwmapi.dll or exceptiondumpdll.dll, the application loads these Trojan horse libraries instead of the legitimate system versions. This behavior allows attackers to inject malicious code that executes with the privileges of the target application, potentially escalating from a standard user account to a higher privilege level depending on the application's execution context. The attack vector is particularly insidious because it requires minimal user interaction beyond opening a PDF file, making it suitable for social engineering campaigns and automated exploitation attempts.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it can enable attackers to establish persistent access to compromised systems while maintaining operational security. Once executed, the malicious DLL can perform various malicious activities including data exfiltration, system reconnaissance, or establishing reverse shells. The vulnerability affects systems running Nuance PDF Reader 6.0 and potentially other versions with similar library loading behaviors, creating a significant attack surface for threat actors targeting enterprise environments where this software is commonly deployed. Security professionals should note that this vulnerability can be leveraged in conjunction with other attack techniques, including credential harvesting and lateral movement, making it a critical component in broader attack chains.
Mitigation strategies for CVE-2010-5209 should focus on both immediate remediation and long-term architectural improvements. The most effective immediate solution involves updating to a patched version of Nuance PDF Reader or implementing application whitelisting policies that prevent execution of unsigned or untrusted DLL files. Organizations should also implement security measures such as disabling the loading of DLLs from user-writable directories and configuring the application's search path to prioritize system directories over user directories. Additionally, system administrators should consider implementing the principle of least privilege and regularly audit application permissions to prevent unauthorized modifications to critical system files. The vulnerability underscores the importance of secure coding practices and proper library loading mechanisms, as outlined in various security standards including those from the Open Web Application Security Project and the Center for Internet Security benchmarks.