RSI.0002.05-18-98.BNU.UUCPD

From: RSI Advise (adviseat_private)
Date: Tue May 19 1998 - 02:31:27 PDT

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    RSI.0002.05-18-98.BNU.UUCPD
    
    
    
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                       Repent Security Incorporated, RSI
                           [ http://www.repsec.com ]
    
    
                           *** RSI ALERT ADVISORY ***
    
    
    --- [CREDIT] --------------------------------------------------------------
    
    Vulnerability found by: Matt Conover <mattat_private>
    
    Notes: This advisory has been brought to you by WSD;
           RSI's official research & development team. <wsdat_private>
           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)
    adviseat_private
    13610 N. Scottsdale Rd.
    Suite #10-326
    Scottsdale, AZ
    85254
    
    [ http://www.repsec.com ]
    
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    Copyright May 1998  RepSec, Inc.
    
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