CVE-2017-2176 in Screensaver Installer
Summary
by MITRE
Untrusted search path vulnerability in screensaver installers (jasdf_01.exe, jasdf_02.exe, jasdf_03.exe, jasdf_04.exe, jasdf_05.exe, scramble_setup.exe, clock_01_setup.exe, clock_02_setup.exe) available prior to May 25, 2017 allows an attacker to gain privileges via a Trojan horse DLL in an unspecified directory.
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Analysis
by VulDB Data Team • 12/26/2020
This vulnerability represents a classic untrusted search path security flaw that affected multiple screen saver installer executables distributed by a major software vendor prior to may 25 2017. The affected executables include jasdf_01 exe through jasdf_05 exe and scramble_setup exe along with clock_01_setup exe and clock_02_setup exe which collectively represent a family of installer programs designed to deploy screen saver components. The vulnerability stems from improper handling of dynamic link library loading sequences where these executables fail to explicitly specify the full path for required dll files during the loading process. This behavior creates a dangerous condition where the system's search path resolution mechanism may inadvertently load maliciously crafted dll files from directories that are searched before the legitimate system directories. According to the common weakness enumeration framework this vulnerability maps directly to cwe 426 untrusted search path which specifically addresses the scenario where applications search for libraries or executables in directories that may contain malicious content. The operational impact of this vulnerability is significant as it allows privilege escalation through a trojan horse attack vector where an attacker can place a malicious dll file in a directory that will be searched before the legitimate system directories. This creates a situation where any user executing one of these installer programs will unknowingly load and execute the malicious code with the privileges of the executing user. The attack requires no special privileges to set up but does require the victim to execute one of the vulnerable installer programs which makes this vulnerability particularly dangerous in enterprise environments where users may have elevated privileges. The specific attack scenario involves placing a malicious dll file with the same name as a legitimate dll that the vulnerable installer expects to load into a directory that appears earlier in the system path such as the current working directory or a user-writable directory. This vulnerability aligns with attack technique t1059 command and scripting interpreter from the attack tactics and techniques framework as attackers can leverage these installer programs to execute malicious code through legitimate system processes. The privilege escalation aspect of this vulnerability is particularly concerning as it can potentially allow attackers to execute code with elevated privileges if the installer programs are executed with administrative rights. The affected software components represent a significant surface area for exploitation as these screen saver installers were commonly distributed and executed by users across various system configurations. The vulnerability demonstrates a fundamental flaw in software design where the principle of least privilege and explicit path resolution were not properly implemented during the development process. Organizations should consider implementing application whitelisting policies and ensuring that all system directories are properly secured to prevent attackers from placing malicious components in locations that may be searched by vulnerable applications. The vulnerability also highlights the importance of proper input validation and explicit path resolution in all system components that load external libraries or executables to prevent similar issues from occurring in other software components. Security professionals should also consider implementing monitoring solutions that can detect when vulnerable executables are being executed and when suspicious dll files are being loaded from unexpected locations to provide additional layers of defense against this type of attack vector.
The vulnerability presents a clear risk to system integrity and user security as it exploits the fundamental trust that operating systems place in the search path mechanism. The specific nature of the flaw means that any user with the ability to write files to directories that are searched by these installers can potentially compromise the system. This type of vulnerability is particularly dangerous because it can be exploited silently without requiring user interaction beyond executing the vulnerable installer program. The attack vector represents a classic example of how insufficient input validation and improper library loading can create security holes that are difficult to detect and remediate. The affected software family demonstrates how seemingly innocuous components like screen saver installers can become attack vectors when not properly secured against untrusted search path conditions. The vulnerability's impact extends beyond individual systems as it can be leveraged to establish persistent access or escalate privileges within a compromised environment. Security practitioners should recognize that this vulnerability type often indicates broader design flaws in software development practices and should be addressed through comprehensive code review processes that enforce secure coding standards and explicit path resolution mechanisms.