CVE-2017-10887 in BOOK WALKER
Summary
by MITRE
Untrusted search path vulnerability in BOOK WALKER for Windows Ver.1.2.9 and earlier allows an attacker to gain privileges via a Trojan horse DLL in an unspecified directory.
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Analysis
by VulDB Data Team • 12/08/2019
The vulnerability identified as CVE-2017-10887 represents a critical untrusted search path weakness affecting BOOK WALKER version 1.2.9 and earlier on Windows systems. This flaw resides in the application's dynamic link library loading mechanism, where the software fails to properly validate or restrict the directories from which it loads executable components. The vulnerability manifests when the application searches for required DLL files in a predictable order that includes user-writable directories, creating an opportunity for malicious actors to place a crafted Trojan horse DLL in a location that will be searched before legitimate system libraries.
This security weakness directly maps to CWE-427 Uncontrolled Search Path Element, a well-documented software flaw that enables attackers to execute arbitrary code by manipulating the library search order. The vulnerability operates under the principle that applications often search for dynamic link libraries in a specific sequence including the current working directory, followed by system directories, and potentially user-writable locations. When an application loads a DLL from an untrusted location due to this search path issue, it effectively grants the attacker the ability to execute code with the privileges of the running process, which typically corresponds to the user's context or potentially system privileges if the application runs with elevated permissions.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass potential system compromise and data exfiltration. An attacker exploiting this flaw can replace legitimate DLL files with malicious counterparts, potentially gaining unauthorized access to sensitive user data, system resources, or network connections. The vulnerability affects Windows environments where BOOK WALKER is installed, and its exploitation risk increases when users have write permissions to directories that may be searched during DLL loading operations. This weakness particularly threatens enterprise environments where users may have elevated privileges or where the application is used in conjunction with other potentially vulnerable software components.
Mitigation strategies for CVE-2017-10887 should prioritize immediate remediation through software updates to versions that address the untrusted search path issue. Organizations should implement application whitelisting policies that restrict which DLLs can be loaded by BOOK WALKER and other applications, effectively preventing unauthorized code execution. System administrators should also conduct comprehensive security audits to identify and eliminate writable directories in the application's search path, particularly those accessible to non-privileged users. The implementation of DEP (Data Execution Prevention) and ASLR (Address Space Layout Randomization) can further complicate exploitation attempts, though these protections alone do not fully address the underlying search path vulnerability. Additionally, regular security assessments and penetration testing should be conducted to identify similar weaknesses in other applications and systems, as this vulnerability type remains prevalent in legacy software applications. The ATT&CK framework categorizes this technique under T1055 Process Injection and T1068 Exploitation for Privilege Escalation, highlighting the broader threat landscape where such vulnerabilities serve as entry points for more sophisticated attacks.