Samba 3.x SMBD Remote Denial of Service Vulnerability
iDEFENSE Security Advisory 09.13.04b www.idefense.com/application/poi/display?id=139&type=vulnerabilities September 13, 2004
Samba is a software suite that provides file and print services to SMB/CIFS clients, such as Microsoft Windows platforms. For more information see:
An unauthenticated remote user can cause a resource exhaustion attack by sending multiple malformed requests to an affected server. Each request spawns a new process, which enters an infinite loop.
This attack takes very little bandwidth to cause the machine to stop responding. Each request from the exploit tested was only 358 bytes, and a Redhat Fedora Core 1 machine with 512 megabytes of RAM and 512 megabytes of swap took fewer than 4000 requests to render it unusable.
iDEFENSE has confirmed Samba 3.0.2 and 3.0.4 are vulnerable.
The vendor has confirmed that Samba 3.0.x prior to and including v3.0.6 are vulnerable.
Restricting access to the server by using the "hosts allow" setting in smb.conf and/or applying firewall rules may help mitigate this vulnerability.
VI. VENDOR RESPONSE
The patch file for Samba 3.0.5 addressing [the] bug (samba-3.0.5-DoS.patch) can be downloaded from:
VII. CVE INFORMATION
The Common Vulnerabilities and Exposures (CVE) project has assigned the names CAN-2004-0807 to these issues. This is a candidate for inclusion in the CVE list (http://cve.mitre.org), which standardizes names for security problems.
VIII. DISCLOSURE TIMELINE
09/02/2004 Initial vendor notification 09/02/2004 iDEFENSE clients notified 09/02/2004 Vendor response 09/13/2004 Coordinated public disclosure
The discoverer wishes to remain anonymous.
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X. LEGAL NOTICES
Copyright (c) 2004 iDEFENSE, Inc.
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