Subject: Samba 3.0.x Denial of Service Flaw Summary: (i) A DoS bug in smbd may allow an unauthenticated user to cause smbd to spawn new processes each one entering an infinite loop. After sending a sufficient amount of packets it is possible to exhaust the memory resources on the server. (ii) A DoS bug in nmbd may allow an attacker to remotely crash the nmbd daemon. Affected Versions: Defect (i) affects Samba 3.0.x prior to and including v3.0.6. Defect (ii) affects Samba 3.0.x prior to and including v3.0.6. Patch Availability: The patch file for Samba 3.0.5 addressing both bugs (samba-3.0.5-DoS.patch) can be downloaded from http://download.samba.org/samba/ftp/patches/security/ Description ----------- CAN-2004-0807: A defect in smbd's ASN.1 parsing allows an attacker to send a specially crafted packet during the authentication request which will send the newly spawned smbd process into an infinite loop. Given enough of these packets, it is possible to exhaust the available memory on the server. CAN-2004-0808: A defect in nmbd's process of mailslot packets can allow an attacker to anonymously crash nmbd. Protecting Unpatched Servers ---------------------------- The Samba Team always encourages users to run the latest stable release as a defense of against attacks. However, under certain circumstances it may not be possible to immediately upgrade important installations. In such cases, administrators should read the "Server Security" documentation found at http://www.samba.org/samba/docs/server_security.html. Credits -------- Both security issues were reported to Samba developers by iDEFENSE (http://www.idefense.com/). The defect discovery was anonymously reported to iDEFENSE via their Vulnerability Contributor Program (http://www.idefense.com/poi/teams/vcp.jsp). -- Our Code, Our Bugs, Our Responsibility. -- The Samba Team