CVE-2011-0570 in Acrobat Reader
Summary
by MITRE
Untrusted search path vulnerability in Adobe Reader and Acrobat 10.x before 10.0.1, 9.x before 9.4.2, and 8.x before 8.2.6 on Windows allows local users to gain privileges via a Trojan horse DLL in the current working directory, a different vulnerability than CVE-2011-0562 and CVE-2011-0588.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 10/16/2021
The vulnerability described in CVE-2011-0570 represents a classic untrusted search path issue affecting Adobe Reader and Acrobat versions across multiple release streams. This flaw exists within the Windows implementation of these applications and stems from improper handling of dynamic link library loading mechanisms. The vulnerability specifically affects versions 10.x before 10.0.1, 9.x before 9.4.2, and 8.x before 8.2.6, creating a persistent security risk for users operating these software components on Windows platforms. The issue manifests when the application attempts to load DLLs without properly validating the source or path of these libraries, creating opportunities for malicious actors to exploit the trust relationship between the application and its dependencies.
The technical exploitation of this vulnerability occurs through a Trojan horse DLL placement attack within the current working directory of the Adobe application. When Adobe Reader or Acrobat executes and attempts to load a required DLL component, the system searches through a predefined list of directories including the current working directory. This search order behavior creates an opportunity for local attackers to place a malicious DLL with the same name as a legitimate library that the application expects to load. The vulnerability is classified under CWE-427, which specifically addresses Untrusted Search Path, and represents a variant of privilege escalation attacks that leverage the trust model inherent in application loading mechanisms. This particular implementation flaw does not require elevated privileges to exploit, as the malicious DLL can be placed by any local user with write access to the working directory.
The operational impact of CVE-2011-0570 extends beyond simple privilege escalation to encompass potential full system compromise when combined with other attack vectors. Local attackers can leverage this vulnerability to execute arbitrary code with the privileges of the Adobe application process, which typically runs with elevated permissions when processing certain document types. The vulnerability creates a persistent backdoor opportunity where attackers can maintain access to systems even after initial compromise, as the malicious DLL remains in the working directory and will be loaded whenever the application is executed. This vulnerability is distinct from related issues such as CVE-2011-0562 and CVE-2011-0588, which address different aspects of Adobe's security model, but together they demonstrate a pattern of inadequate library loading security within the Adobe product suite. The ATT&CK framework categorizes this vulnerability under privilege escalation techniques, specifically leveraging trusted developer utilities and system libraries to bypass security controls.
Mitigation strategies for CVE-2011-0570 focus on both immediate patching and operational security measures. The primary recommendation involves applying the official Adobe security patches released for versions 10.0.1, 9.4.2, and 8.2.6 respectively, which address the root cause by implementing proper DLL loading validation. Organizations should also implement directory permissions controls to restrict write access to Adobe application directories and working folders, particularly preventing local users from placing files in locations where the application might load dependencies. System administrators should consider implementing application whitelisting policies that restrict which DLLs can be loaded by Adobe applications, and monitor for unusual file creation patterns in Adobe working directories. Additionally, network segmentation and privilege separation can help limit the potential impact of successful exploitation, as the vulnerability requires local access to the target system to be effectively leveraged. The vulnerability serves as a reminder of the critical importance of proper library loading security in applications and the necessity of validating all dynamic component dependencies against trusted sources.