RSI.0002.05-18-98.BNU.UUCPD |::::. |:::::: |:::::. |:::::: |:::::: |:::::. |.. :: |.. |.. :: |.. |.. |.. :: |::::: |::::: |::::: :::::: |:::::: |::::: |:: |:: :: |:: |:: |:: |:: |:: :: |:: :: |:::::: |:: |:::::: |:::::: |:::::: Repent Security Incorporated, RSI [ http://www.repsec.com ] *** RSI ALERT ADVISORY *** --- [CREDIT] -------------------------------------------------------------- Vulnerability found by: Matt Conover Notes: This advisory has been brought to you by WSD; RSI's official research & development team. Webpage: http://www.w00w00.org Authors: Matt Conover & Mark Zielinski --- [SUMMARY] ------------------------------------------------------------- Announced: April 21, 1998 Report code: RSI.0002.05-18-98.BNU.UUCPD Report title: BNU uucpd Vulnerability: Insufficient bounds checking Vendor status: NetBSD: Contacted, patch information below OpenBSD: Contacted, patch information below Solaris: Contacted, awaiting patch information Patch status: Patch available for certain Operating Systems at the end of this advisory Platforms: OSF 1.0, 2.0, SunOS 4.1.3, 4.1.4 Solaris 2.2, 2.3, 2.4, 2.5.1 NetBSD 1.3, 1.3.1 OpenBSD 2.1, 2.2 Not affected: FreeBSD 2.x BSDi 2.x, 3.x RedHat Linux 4.x, 5.x Slackware Linux 3.x Reference: http://www.repsec.com/advisories.html Impact: If exploited, an attacker could locally compromise root on your system. --- [DETAILS] ------------------------------------------------------------- Problem: Upon successfully logging into a system with uucpd, the daemon will attempt to record wtmp information. However, due to insufficient bounds checking, a buffer overflow can result when uucpd 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 into the system. The attacker must have an account on the system, which will allow this to be exploited. This problem is present in BNU uucpd. This is not installed by default on every operating system. This also may not always run as root. Known vulnerable Operating Systems include: OSF 1.0, 2.0, SunOS 4.1.3, 4.1.4 Solaris 2.2, 2.3, 2.4, 2.5.1 NetBSD 1.3, 1.3.1 OpenBSD 2.1, 2.2 Operating Systems not vulnerable: FreeBSD 2.x BSDi 2.x, 3.x RedHat Linux 4.x, 5.x Slackware Linux 3.x For more information on this type of attack, point your web browsers to http://www.repsec.com/bofs.html. --- [FIX] ----------------------------------------------------------------- Solution: A generic patch has been made publically available by the RSI staff. --- [PATCH] --------------------------------------------------------------- Solution: Apply the following patch to uucpd.c: --- uucpd.old.c Thu Feb 6 06:34:45 1997 +++ uucpd.c Tue Apr 7 16:37:46 1998 @@ -300,7 +300,8 @@ time(&ll.ll_time); lseek(f, pw->pw_uid * sizeof(struct lastlog), 0); - strcpy(line, remotehost); + strncpy(line, remotehost, sizeof(line)-1); SCPYN(ll.ll_line, line); SCPYN(ll.ll_host, remotehost); (void) write(f, (char *) &ll, sizeof ll); For NetBSD's patch please refer to: http://www.repsec.com/advisory/0002.patch.html --------------------------------------------------------------------------- Repent Security Incorporated (RSI) advise@repsec.com 13610 N. 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