CVE-2004-1517 in IMsecure
Summary
by MITRE
Zone Labs IMsecure and IMsecure Pro before 1.5 allow remote attackers to bypass Active Link Filtering via an instant message containing a URL with hex encoded file extenstions.
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Analysis
by VulDB Data Team • 06/22/2018
The vulnerability described in CVE-2004-1517 affects Zone Labs IMsecure and IMsecure Pro versions prior to 1.5, representing a significant security flaw in instant messaging client filtering mechanisms. This issue resides in the Active Link Filtering functionality that is designed to prevent malicious content from being transmitted through instant messaging channels. The vulnerability specifically targets the validation of file extensions within URLs contained in instant messages, creating a pathway for attackers to circumvent security controls that should otherwise block potentially harmful file types.
The technical flaw exploits a weakness in the URL parsing and validation logic where the system fails to properly decode hex encoded file extensions within URLs. When an attacker crafts an instant message containing a URL with hex encoded file extensions such as .exe being encoded as %2E%65%78%65, the filtering system does not adequately decode these values before performing extension validation. This allows malicious file types to pass through security controls that would normally block them, as the system evaluates the hex encoded version rather than the decoded extension. The vulnerability specifically targets the input sanitization process within the messaging client's security framework, demonstrating a failure in proper encoding handling and validation procedures.
The operational impact of this vulnerability is substantial as it enables remote attackers to bypass critical security controls designed to protect users from malicious file downloads. Attackers can craft deceptive instant messages that appear benign while containing malicious executables or other harmful file types that would normally be blocked by the security filtering system. This creates a significant risk for organizations relying on IMsecure for corporate communications, as it undermines the fundamental security assumptions of the messaging platform. The vulnerability essentially allows attackers to perform a form of content type evasion that directly contradicts the intended security posture of the software, potentially leading to unauthorized code execution, malware deployment, and other malicious activities.
This vulnerability aligns with CWE-184, which addresses incomplete input validation, and demonstrates characteristics consistent with CWE-707, concerning improper neutralization of input during web application processing. The issue also relates to ATT&CK technique T1190, which involves exploiting vulnerabilities in software applications to gain unauthorized access. Organizations should implement immediate mitigations including updating to Zone Labs IMsecure Pro version 1.5 or later, which contains the necessary patches to properly decode and validate URL file extensions. Additional defensive measures should include implementing network-level filtering rules that block suspicious instant messaging traffic, deploying enhanced email and web filtering solutions, and conducting security awareness training to help users recognize potentially malicious instant messages. System administrators should also consider implementing additional monitoring of instant messaging traffic patterns to detect anomalous behavior that might indicate exploitation attempts.