CVE-2005-3421 in Hyper Estraier
Summary
by MITRE
estcmd in Hyper Estraier 1.0.1 on Windows systems allows remote attackers to read unauthorized files via a crafted search request for a filename that contains Unicode characters.
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Analysis
by VulDB Data Team • 07/27/2017
The vulnerability identified as CVE-2005-3421 affects Hyper Estraier version 1.0.1 on Windows operating systems, specifically within the estcmd component that handles search requests. This issue represents a classic path traversal vulnerability that exploits improper input validation mechanisms in the search functionality. The flaw occurs when the system processes search queries containing Unicode characters in filenames, allowing malicious actors to manipulate the search parameters to access files outside the intended directory structure. This vulnerability falls under the CWE-22 category of Path Traversal attacks, which is a well-documented weakness in software systems where input validation fails to properly restrict file access paths. The vulnerability is particularly concerning in Windows environments where file system access controls and path resolution mechanisms differ from Unix-like systems, creating additional attack surface opportunities.
The technical implementation of this vulnerability relies on the improper handling of Unicode character sequences within the estcmd search functionality. When a crafted search request is submitted with specific Unicode characters that are interpreted as path traversal sequences, the system fails to properly sanitize or validate these inputs before processing them against the file system. This allows attackers to construct search queries that bypass normal access controls and retrieve unauthorized files from the system. The vulnerability specifically targets Windows systems because of how the operating system handles Unicode file paths and how the Hyper Estraier software processes these paths internally. The attack vector involves sending a specially crafted search request that contains Unicode sequences which, when processed by the estcmd component, result in unintended file system access patterns.
The operational impact of this vulnerability extends beyond simple unauthorized file access, as it can potentially allow attackers to extract sensitive system information, configuration files, or even credentials stored in accessible locations. Attackers could leverage this vulnerability to gain insights into system architecture, identify running services, or discover other potential security weaknesses within the targeted environment. The remote nature of this attack means that an attacker does not require local system access or credentials to exploit the vulnerability, making it particularly dangerous for web-based applications or services that utilize Hyper Estraier for search functionality. This vulnerability aligns with ATT&CK technique T1083 (File and Directory Discovery) and T1566 (Phishing) as attackers may use this access to gather information that can be used for further exploitation or to craft more sophisticated social engineering attacks.
Mitigation strategies for this vulnerability should focus on implementing proper input validation and sanitization within the estcmd component to prevent Unicode character sequences from being interpreted as path traversal attempts. Organizations should apply the vendor-provided patch or upgrade to a version of Hyper Estraier that addresses this specific vulnerability. Network-level protections such as web application firewalls can help detect and block suspicious search requests containing potentially malicious Unicode sequences. Additionally, implementing proper access controls and least privilege principles can limit the damage if exploitation occurs, ensuring that even if an attacker gains access through this vulnerability, they cannot read files beyond the intended scope. System administrators should also monitor for unusual search patterns or access attempts that might indicate exploitation attempts, as this vulnerability can be used as a reconnaissance tool to map system file structures before launching more targeted attacks.