CVE-2010-1638 in Horde
Summary
by MITRE
The IMP plugin in Horde allows remote attackers to bypass firewall restrictions and use Horde as a proxy to scan internal networks via a crafted request to an unspecified test script. NOTE: this is only a vulnerability when the administrator does not follow recommendations in the product s installation documentation.
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Analysis
by VulDB Data Team • 12/30/2017
The vulnerability described in CVE-2010-1638 represents a critical security flaw within the IMP (Internet Messaging Program) plugin of the Horde webmail application ecosystem. This issue specifically targets the proxy functionality that is inherently designed to allow users to access external email services while maintaining network security boundaries. The vulnerability arises from improper input validation and access control mechanisms within the IMP plugin's handling of network requests, creating an unintended pathway for malicious actors to exploit the application's proxy capabilities for unauthorized network scanning activities.
The technical exploitation of this vulnerability occurs through the manipulation of crafted HTTP requests that target an unspecified test script within the Horde application. When properly configured, the IMP plugin includes proxy functionality that should restrict external connections to prevent internal network exposure. However, the flaw allows attackers to bypass these intended restrictions by constructing specific requests that leverage the plugin's legitimate proxy mechanisms to scan internal network segments. This represents a classic case of insecure direct object reference vulnerability where the application fails to properly validate the scope of network operations permitted through its proxy interface. The vulnerability is particularly concerning because it enables attackers to perform reconnaissance activities against internal networks without direct access to those systems, effectively using the compromised webmail application as a pivot point for further attacks.
The operational impact of this vulnerability extends beyond simple network scanning to encompass broader security implications for organizations relying on Horde applications. When exploited, the vulnerability allows attackers to map internal network topology, identify active services, and potentially discover vulnerable internal systems that would otherwise remain hidden from external view. This capability aligns with tactics described in the attack pattern taxonomy where adversaries use compromised systems as stepping stones to expand their operational reach. Organizations may experience unauthorized network reconnaissance activities that could lead to more sophisticated attacks, including credential harvesting, service exploitation, or lateral movement within their internal infrastructure. The vulnerability's exploitation is particularly dangerous because it can occur without direct authentication, relying instead on the legitimate proxy functionality that is typically enabled for legitimate user access to external mail services.
Security mitigations for this vulnerability primarily focus on proper configuration and administrative practices as highlighted in the original CVE description. Organizations must strictly follow the installation documentation recommendations, which typically include disabling unnecessary proxy functionality, implementing proper access controls, and ensuring that network segmentation is properly enforced. The vulnerability demonstrates the critical importance of principle of least privilege in web application security, where functionality should be disabled by default and only enabled when explicitly required. Additionally, organizations should implement network monitoring to detect unusual proxy activity patterns that could indicate exploitation attempts, and should regularly audit their web application configurations to ensure compliance with security best practices. This vulnerability underscores the importance of defense in depth strategies where multiple layers of security controls work together to prevent exploitation, as described in the NIST cybersecurity framework and aligned with common security practices recommended in the OWASP top ten vulnerabilities.