CVE-2005-1045 in Firstclass Desktop Client
Summary
by MITRE
OpenText FirstClass 8.0 client does not properly sanitize strings before passing them to the Windows ShellExecute API, which allows remote attackers to execute arbitrary commands via a UNC path in a bookmark.
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Analysis
by VulDB Data Team • 06/23/2018
The vulnerability identified as CVE-2005-1045 resides within OpenText FirstClass 8.0 client software, specifically targeting the client-side application that handles bookmark navigation. This flaw represents a classic command injection vulnerability that exploits improper input validation mechanisms within the application's handling of network paths. The vulnerability occurs when the client processes bookmark entries that contain Uniform Naming Convention (UNC) paths, which are typically used to reference network resources in Windows environments. The root cause lies in the application's failure to properly sanitize user-supplied input before invoking the Windows ShellExecute API, a critical system function designed to execute programs or open files through the operating system's shell interface.
The technical exploitation of this vulnerability leverages the Windows ShellExecute API's inherent capability to execute commands when provided with specific path formats. When an attacker crafts a malicious bookmark containing a UNC path that includes executable commands or scripts, the FirstClass client processes this input without adequate sanitization. The Windows ShellExecute API interprets the malformed UNC path and executes the embedded commands with the privileges of the user running the FirstClass client application. This behavior aligns with CWE-78, which describes improper neutralization of special elements used in OS commands, and demonstrates how insufficient input validation can lead to arbitrary code execution. The vulnerability specifically affects the client-side component of the FirstClass system, making it particularly dangerous in environments where users may encounter malicious bookmarks in email messages, web pages, or shared network resources.
The operational impact of this vulnerability extends beyond simple command execution, creating a significant security risk for organizations relying on FirstClass for communication and collaboration. Attackers can leverage this weakness to execute malicious payloads, escalate privileges, or establish persistent access to compromised systems. The remote nature of the attack means that exploitation can occur without requiring local access to the target system, making it particularly dangerous in corporate environments where users may inadvertently click on malicious links in emails or web content. This vulnerability falls under the MITRE ATT&CK framework's technique T1059, which covers command and scripting interpreter, specifically targeting the execution of malicious code through shell commands. The risk is amplified by the fact that the attack vector involves user interaction through bookmarks, making it difficult to defend against through traditional network-based security controls alone.
Organizations affected by this vulnerability should implement immediate mitigations including updating to patched versions of FirstClass 8.0, implementing network-level restrictions on UNC path handling, and educating users about the dangers of clicking on untrusted bookmarks or links. System administrators should configure group policies to restrict ShellExecute API usage for non-privileged users and implement application whitelisting to prevent execution of unauthorized programs. The vulnerability highlights the importance of proper input validation and sanitization in client applications, particularly when interfacing with operating system APIs that have elevated privileges. Security teams should also monitor for suspicious network traffic patterns and implement network segmentation to limit the potential impact of successful exploitation. Additionally, organizations should conduct vulnerability assessments to identify other applications that may be susceptible to similar issues involving shell API calls and input handling mechanisms.