-----BEGIN PGP SIGNED MESSAGE----- __________________________________________________________ The U.S. Department of Energy Computer Incident Advisory Capability ___ __ __ _ ___ / | /_\ / \___ __|__ / \ \___ __________________________________________________________ INFORMATION BULLETIN RSI BSDI rlogind Vulnerability June 19, 1998 20:00 GMT Number I-063 ______________________________________________________________________________ PROBLEM: A vulnerability exists using rlogind in all current versions of Berkeley Software Design Inc. (BSDI). PLATFORM: Any server running BSDI with rlogind enabled. DAMAGE: Can create a buffer overflow which may allow an attacker to gain root access. SOLUTION: Disable rlogind until patches are available. ______________________________________________________________________________ VULNERABILITY Disable rlogind on affected systems as soon as possible. Apply ASSESSMENT: the patches as soon as they are made available. ______________________________________________________________________________ [ Start Repent Security Inc. Advisory ] RSI.0004a.06-17-98.BSDI.RLOGIND |:::. |::::: |::::. |::::: |::::: |::::. .. :: .. .. :: .. .. .. :: |:::: |:::: |:::: :::::: |::::: |:::: |: |: :: |: |: |:: |: |: :: |: :: |::::: |: |::::: |::::: |::::: Repent Security Incorporated, RSI [ http://www.repsec.com ] *** RSI ALERT ADVISORY *** - --- [CREDIT] -------------------------------------------------------------- Mark Zielinski: Research and development, author of advisory. - --- [SUMMARY] ------------------------------------------------------------- Announced: June 17, 1998 Report code: RSI.0004a.06-17-98.BSDI.RLOGIND Report title: BSDI rlogind Vulnerability: A buffer overflow exists in rlogind that could allow remote root access on servers running BSDI 2.1 or earlier Vendor status: Has been contacted on 6-17-98 Patch status: No vendor patch currently available Platforms: BSDI 2.0, 2.1 Not affected: BSDI 3.0, 3.1 FreeBSD-Current (2.2.6) NetBSD-Current (1.3) OpenBSD 2.1, 2.2, 2.3 Reference: http://www.repsec.com/advisories.html Impact: If exploited, an attacker could potentially compromise root access on your server - --- [DETAILS] ------------------------------------------------------------- Problem: A vulnerability exists in BSDI rlogind that has the potential to allow an attacker to gain remote root access on any server running BSDI 2.1 or earlier with rlogind enabled. This vulnerability occurs as a result of inverse resolution of IP addresses to hostnames. An attacker in control of a DNS server can configure the records for a specific IP address to resolve with a name larger than rlogind can handle. Due to insufficient bounds checking, a buffer overflow can result when rlogind attempts to copy the connecting hostname into a buffer with a predefined size. While overwriting the buffer, the attacker can manipulate the stack and execute their own commands, possibly gaining root access on the server. For more information on this type of attack, point your web browsers to: http://www.repsec.com/bofs.html. - --- [FIX] ----------------------------------------------------------------- Solution: Disable rlogind until Berkeley Software Design Inc. can provide a patch. To disable rlogind: 1. su to the root account 2. kill -9 `ps -aux | grep rlogind | awk '{print $2}'` 3. edit /etc/inetd.conf with your favorite editor 4. place a # in front of any lines beginning with "login" - --- [PATCH] --------------------------------------------------------------- Solution: Wait for Berkeley Software Design Inc. to release an official patch or upgrade to 3.0 or higher. - --------------------------------------------------------------------------- Repent Security Incorporated (RSI) 13610 N. Scottsdale Rd. Suite #10-326 Scottsdale, AZ 85254 E-mail: advise@repsec.com WWW: http://www.repsec.com FTP: ftp://ftp.repsec.com [ End Repent Security Inc. Advisory ] ______________________________________________________________________________ CIAC wishes to acknowledge the contributions of Repent Security Inc. for the information contained in this bulletin. ______________________________________________________________________________ CIAC, the Computer Incident Advisory Capability, is the computer security incident response team for the U.S. Department of Energy (DOE) and the emergency backup response team for the National Institutes of Health (NIH). CIAC is located at the Lawrence Livermore National Laboratory in Livermore, California. CIAC is also a founding member of FIRST, the Forum of Incident Response and Security Teams, a global organization established to foster cooperation and coordination among computer security teams worldwide. CIAC services are available to DOE, DOE contractors, and the NIH. 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Neither the United States Government nor the University of California nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial products, process, or service by trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation or favoring by the United States Government or the University of California. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or the University of California, and shall not be used for advertising or product endorsement purposes. 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