The original advisory [RSI.0010.10-21-98.IRIX.AUTOFSD] was sent to Silicon Graphics Inc. on Fri, 2 Oct 1998 17:48:43, and detailed a local vulnerability against the 'autofsd' daemon. Further testing has revealed that this issue extends to remote attackers on the Irix platform as well as the AIX platform. SGI was contacted again on Wed, 11 Nov 1998 18:57:07 and made aware of the remote vulnerability. Mention of the remote vulnerability has been made in SGI's security adivsory [19981005-01-PX] as well as IBM's advisory [ERS-SVA-E01-1998:004.1]. RSI is releasing the following update to disclose further details on the attack. RSI.0010a.11-29-98.IRIX.AUTOFSD |:::. |::::: |::::. |::::: |::::: |::::. .. :: .. .. :: .. .. .. :: |:::: |:::: |:::: :::::: |::::: |:::: |: |: :: |: |: |:: |: |: :: |: :: |::::: |: |::::: |::::: |::::: Repent Security Incorporated, RSI [ http://www.repsec.com ] *** RSI ALERT ADVISORY *** --- [CREDIT] -------------------------------------------------------------- Mark Zielinski : Discovered the vulnerability, author of the advisory --- [SUMMARY] ------------------------------------------------------------- Announced: October 2, 1998 Report code: RSI.0010a.11-29-98.IRIX.AUTOFSD Report title: IRIX autofsd Vulnerability: Please see the details section Vendor status: SGI contacted on October 2, 1998 Patch status: Information on patches is available Platforms: AIX 4.3, IRIX 6.2, 6.3, 6.4, 6.5, 6.5.1 Update: Previous advisory listed this as a local issue. Further testing indicates this is remotely vulnerable. Reference: http://www.repsec.com/advisories.html Impact: If exploited, an attacker could potentially compromise root access both locally and remotely on your server NOTE: IRIX versions 5.3, 6.0, and 6.1 were NOT tested by RSI, however they could be subject to the same vulnerability. AIX 4.1.x and 4.2.x are NOT vulnerable. --- [DETAILS] ------------------------------------------------------------- Description: Autofsd is an RPC server which answers file system mount and umount requests from the autofs file system. It uses local files or name service maps to locate file systems to be mounted. Problem: Remote users can send requests to the autofsd daemon and execute arbitrary commands as the superuser. Since the autofsd daemon runs as root on a fixed UDP port, it becomes very dangerous. This will allow any hacker to remotely connect straight to the port without having to ask the portmapper. It is a common mistake for system administrators to disable portmapper but forget about the rpc services running in the background. Details: Upon receiving a map argument from a client, the server will attempt to verify if it is executable or not. If autofsd determines the map has an executable flag, the server will append the client's key and attempt to execute it. By sending a map name that is executable on the server, and a key beginning with a semicolon or a newline followed by a command, unprivileged users can execute arbitrary commands as the superuser. The problem occurs when the server appends the key to the map and attempts to execute it by calling popen. Since popen executes the map and key you specify by invoking a shell, it is possible to force it into executing commands that were not meant to be executed. --- [THANKS] -------------------------------------------------------------- RSI would like to thank APK for his input on the remote aspect of this vulnerability. --- [FIX] ----------------------------------------------------------------- Solution: SGI patch information can be found in their advisory located at: ftp://sgigate.sgi.com/security/19981005-01-A IBM is working on the following fixes which will be available soon. AIX 4.1.x: not vulnerable AIX 4.2.x: not vulnerable AIX 4.3.x: IX83752 AIX patch can be found at: ftp://aix.software.ibm.com/aix/efixes/security/automountd.tar.Z Filename sum md5 ================================================================== autofs.ext 26103 117 4afedf8fbe411e8be2588fa8843211ae automountd 16386 83 eb4c2e1c4cfe609b2ecba0c6a704640c --------------------------------------------------------------------------- Repent Security Incorporated (RSI) 13610 N. Scottsdale Rd. 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