CVE-2001-1004 in Gnutella
Summary
by MITRE
Cross-site scripting (CSS) vulnerability in gnut Gnutella client before 0.4.27 allows remote attackers to execute arbitrary script on other clients by sharing a file whose name contains the script tags.
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Analysis
by VulDB Data Team • 09/30/2025
The vulnerability identified as CVE-2001-1004 represents a classic cross-site scripting flaw within the gnut Gnutella client software, specifically affecting versions prior to 0.4.27. This vulnerability operates within the peer-to-peer file sharing ecosystem where users exchange files directly with one another without centralized oversight. The gnut client, which was part of the Gnutella network protocol implementation, failed to properly sanitize file names before displaying them to users, creating an exploitable condition that could be leveraged by malicious actors to inject arbitrary scripts into the client interface. The vulnerability stems from inadequate input validation and output encoding mechanisms within the client's user interface rendering process, where file names containing script tags would be executed as active code rather than treated as static text.
The technical exploitation of this vulnerability occurs when a remote attacker crafts a malicious file name containing HTML or JavaScript code and shares it within the Gnutella network. When another user's gnut client attempts to display this file in its interface, the embedded script tags are interpreted and executed by the client's rendering engine, potentially allowing attackers to perform actions such as stealing session cookies, redirecting users to malicious sites, or executing arbitrary commands on the victim's system. This type of vulnerability falls under the Common Weakness Enumeration category CWE-79, which specifically addresses Cross-Site Scripting flaws, and aligns with the ATT&CK framework's technique T1059.007 for Scripting, where adversaries leverage client-side scripting to compromise systems. The attack vector is particularly dangerous in peer-to-peer environments where trust is implicit between users and where network participants may not validate the legitimacy of shared content.
The operational impact of CVE-2001-1004 extends beyond simple script execution, as it represents a fundamental security flaw in how the gnut client processes user-generated content within its graphical interface. Users who are unaware of the malicious file sharing practices within the Gnutella network could inadvertently trigger the execution of harmful scripts simply by browsing shared file lists or viewing file metadata. This vulnerability essentially transforms the legitimate file sharing functionality of the Gnutella protocol into a vector for malicious code delivery, undermining the security assumptions of peer-to-peer networks. The attack requires minimal technical expertise from the adversary, making it particularly dangerous as it could be exploited by casual attackers without sophisticated knowledge of web application security. The vulnerability also highlights the broader security challenges inherent in distributed peer-to-peer systems where traditional security controls like web application firewalls or server-side input validation cannot be effectively applied.
Mitigation strategies for this vulnerability require immediate patching of the gnut client to version 0.4.27 or later, which included proper input sanitization and output encoding mechanisms to prevent script execution. Organizations and users should implement additional defensive measures such as disabling automatic file name display in potentially malicious contexts, employing network monitoring tools to detect unusual file sharing patterns, and educating users about the risks of sharing or downloading files from untrusted sources. The fix implemented by the gnut development team likely involved implementing proper HTML escaping for all file names displayed in the user interface, ensuring that any script tags or HTML characters are rendered as literal text rather than executable code. This approach aligns with security best practices for preventing XSS vulnerabilities and demonstrates the importance of input validation in client-side applications. Network administrators should also consider implementing content filtering solutions that can detect and block file names containing suspicious script patterns, while regular security audits of peer-to-peer client implementations should be conducted to identify similar vulnerabilities in other distributed applications.