CVE-2000-0939 in Samba
Summary
by MITRE
Samba Web Administration Tool (SWAT) in Samba 2.0.7 allows remote attackers to cause a denial of service by repeatedly submitting a nonstandard URL in the GET HTTP request and forcing it to restart.
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Analysis
by VulDB Data Team • 05/28/2018
The vulnerability identified as CVE-2000-0939 represents a significant denial of service flaw within the Samba Web Administration Tool SWAT component of Samba version 2.0.7. This issue stems from inadequate input validation mechanisms within the HTTP request processing functionality of the web administration interface, specifically when handling GET requests containing nonstandard URL parameters. The vulnerability manifests when remote attackers exploit the tool's failure to properly sanitize or reject malformed HTTP requests, leading to system instability and forced restart conditions that disrupt legitimate administrative operations.
The technical implementation of this vulnerability resides in the HTTP request parsing logic of SWAT, where the tool does not adequately validate the structure or content of incoming URL parameters during GET requests. When a malformed or nonstandard URL is submitted repeatedly, the parsing routine encounters unexpected input that triggers an internal error condition, causing the service to terminate unexpectedly and restart automatically. This behavior constitutes a classic denial of service attack vector that exploits the software's lack of robust error handling and input validation mechanisms. The vulnerability operates at the application layer and specifically affects the web server component of Samba's administration interface, making it accessible over network connections without requiring authentication credentials.
From an operational impact perspective, this vulnerability creates substantial disruption for network administrators who rely on the Samba Web Administration Tool for system management tasks. The forced restarts effectively deny legitimate users access to the administration interface, potentially interrupting critical network services and requiring manual intervention to restore functionality. The vulnerability's exploitability is relatively straightforward, as attackers need only submit malformed HTTP requests repeatedly to trigger the service disruption. This makes it particularly dangerous in environments where administrators depend on continuous access to network configuration and user management capabilities, as the DoS condition can persist until the service is manually restarted or the system is rebooted.
The vulnerability aligns with CWE-20, which addresses improper input validation, and demonstrates characteristics consistent with the ATT&CK technique T1499.004 for network denial of service attacks. Organizations utilizing Samba 2.0.7 systems should implement immediate mitigations including network-level filtering to restrict access to the SWAT interface, deployment of intrusion detection systems to monitor for suspicious HTTP request patterns, and implementation of rate limiting controls to prevent rapid submission of malformed requests. Additionally, upgrading to patched versions of Samba that address this input validation flaw represents the most effective long-term solution. System administrators should also consider disabling the SWAT interface entirely when not actively needed, as it represents a privileged access point that can be exploited to cause service disruption without requiring authentication credentials, making it particularly attractive to attackers seeking to compromise network availability.