computer-security/security-patches FAQ

# Security Patches FAQ

Version: 2.1

This Security FAQ is a resource provided by:

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> http://www.iss.net/
> ftp ftp.iss.net /pub/faq/

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> subscribe alert

## Security Patches FAQ for your System: The Patch List

As new systems become accessible by networks there is a need for security. Many systems are shipped insecure which puts the responsibility on the customers to find and apply patches. This FAQ will be a guide for the many administrators who want to secure their systems.

This FAQ is broken down into the different sections:

1. Generic Things to Look For
2. Type of Operating System and its Vulnerabilities.
   - AIX
   - DEC
   - HPUX
   - NEXT
   - SCO
   - Sun Microsystems
   - SGI
3. Particular Vulnerabilities
   - FTP
   - Sendmail
   - HTTPd (WWW)
   - Rdist
   - IP Spoofing attacks
   - Hijacking terminal connections
4. Unpatched Vulnerabilities (Bugs that the Vendor has not Fixed)

## Part 1 - Generic Things to Look For

- Firewalling is one of the best methods of stopping pontential intruders. Block all UDP traffic except for DNS and nameserver ports. Block all source routing and rlogin and rsh at the router if possible.

- Run ISS (Internet Security Scanner) regulary. This package allows an administrator to do an audit of the network and notify him of any security misconfigurations or anomalies that allow intruders in therefore allowing him to take corrective measures before his network is compromised. It is available on aql.gatech.edu:/pub/security/iss

- Run Tiger regularly. It is available on net.tamu.edu:/pub/security/TAMU

  ### Password Security

  - Use one-time password technology like s/key. This package makes sniffing passwords useless since the password that goes over the network is only used once. It is available on ftp:thumper.bellcore.com:/pu b/nmh/skey

  - Shadowing passwords is useful against dictionary passwd cracking attacks.

  - Replace passwd with a program that will not allow your users to pick easy passwords.

  - Check for all easy-to-guess passwords with Crack which is available on ftp.cert.org:/pub/tools/crack by Alec Muffett (alecm@sun.com) .

- Do a rpcinfo -p command and check to make sure rexd is not running.

- TFTP should be turned off unless needed because it can be used to grab password files remotely.

- Make sure there is no '+' in /etc/hosts.equiv or any .rhosts.

- Make sure there are no '#' in /etc/hosts.equiv or any .rhosts.

- Make sure there are no funny commands in any .forward.

- Make sure there are no cleartext passwords in any .netrc.

- Do a showmount -e command to see your exports and make sure they are restricted to only trusted hosts. Make sure all exports have an access list.

- Use Xauthority when using X11 or openwin.

- You may want to remove the suid from rdist, chill, pstat, and arp. They are known to cause security problems on generic default machine.

- Run tripwire regularly. It is available on coast.cs.purdue.edu:/pub/COAST/Tripwire

- Run COPS regulary. It is available on ftp.cert.org:/pub/tools/cops

- Run a TCP Wrapper. It is available on ftp.win.tue.nl:/pub/security/tcp_wrappers_6.3.shar.Z

- Identd may help locate accounts that intruders are using on remote and local machines. It is on ftp.lysator.liu.se:/pub/ident/servers

## Part 2 - Type of Operating System and its Vulnerabilities

To find some of the newer patches, using archie and xarchie can be a useful tool. Some caution must be used when using patches obtained from FTP sites. It is known that some ftp sites have been compromised in the past and files were replaced with trojans. Please verify the checksums for the patches.

### AIX

Fixdist is a X Windows front end to the AIX PTF (Patch) Database. Fixdist package available at ftp:aix.boulder.ibm.com

Fixdist requirements:

Software:

- AIX for RISC System/6000 Version 3.2.4 or above.
- AIX TCPIP Facilities (bosnet.tcpip.obj)
- AIXwindows 1.2.0 (X11R4) or AIXwindows 1.2.3 (X11R5).

Connection Requirements

- The fixdist utility communicates to the ftp server using anonymous ftp. There is no mail transport or Telnet requirement. The server is currently available only on the Internet. If you are able to download the utility, you are fully enabled use fixdist.

Fixdist does not "install" any PTFs onto your system. It just transfers the fixes to a target directory on your RISC System/6000.

The AIX support line is at

> http://aix.boulder.ibm.com/pbin-usa/getobj.pl?/pdocs-usa/public.html/

From that page, you can link to a forms-based keyword search, which you can use to query with the terms "aix" and "security". The direct link for the keyword search is:

> http://aix.boulder.ibm.com/pbin-usa/pub_search.pl

To turn off IP Forwarding and Source Routing, add the following to /etc/rc.net:

> /usr/sbin/no -o ipforwarding=0
> /usr/sbin/no -o ipsendredirects=0
> /usr/sbin/no -o nonlocsrcroute=0

### DEC

Security kits are available from Digital Equipment Corporation by contacting your normal Digital support channel or by request via DSNlink for electronic transfer.

Digital Equipment Corporation strongly urges Customers to upgrade to a minimum of ULTRIX V4.4 and DEC OSF/1 V2.0 then apply the Security Enhanced Kit.

- Please refer to the applicable Release Note information prior to upgrading your installation.

    KIT PART NUMBERS and DESCRIPTIONS

    CSC PATCH #

    CSCPAT_4060  V1.0   ULTRIX    V4.3 thru V4.4  (Includes DECnet-ULTRIX V4.2)
    CSCPAT_4061  V1.0   DEC OSF/1 V1.2 thru V2.0

             These kits will not install on versions previous to ULTRIX V4.3
             or DEC OSF/1 V1.2.

    The ULTRIX Security Enhanced kit replaces the following images:
    /usr/etc/comsat                 ULTRIX V4.3, V4.3a, V4.4
    /usr/ucb/lpr                    "                      "
    /usr/bin/mail                   "                      "
    /usr/lib/sendmail               "                      "
                        *sendmail - is a previously distributed solution.

    /usr/etc/telnetd                ULTRIX V4.3, V4.3a only

    For DECnet-ULTRIX V4.2  installations:

    /usr/etc/dlogind
    /usr/etc/telnetd.gw

    The DEC OSF/1 Security Enhanced kit replaces the following images:

    /usr/sbin/comsat                DEC OSF/1 V1.2, V1.3 V2.0
    /usr/bin/binmail
    /usr/bin/lpr                    "                       "

    /usr/sbin/sendmail              DEC OSF/1 V1.2, V1.3  only
                        *sendmail - is a previously distributed solution.
    /usr/bin/rdist                  "                       "
    /usr/shlib/libsecurity.so       DEC OSF/1 V2.0 only

### HPUX

In order to retrieve any document that is described in this index, send the following in the TEXT PORTION OF THE MESSAGE to support@support.mayfield.hp.com:

send doc xxxxxxxxxxxx

Summary of 'Security Bulletins Index' documents

    Document Id    Description
    HPSBMP9503-003 Security Vulnerability (HPSBMP9503-003) in MPE/iX releases
    HPSBMP9503-002 Security Vulnerability (HPSBMP9503-002) in MPE/iX releases
    HPSBMP9503-001 Security Vulnerability (HPSBMP9503-001) in MPE/iX releases
    HPSBUX9502-024 /usr/lib/sendmail has two security vulnerabilities
    HPSBUX9502-023 Security vulnerability in `at' & `cron'
    HPSBUX9502-022 Security Vulnerability involving malicious users
    HPSBUX9502-021 No current vulnerability in /bin/mail (or /bin/rmail)
    HPSBUX9501-020 Security Vulnerability in HP Remote Watch
    HPSBUX9411-019 Security Vulnerability in HP SupportWatch
    HPSBUX9410-018 Security Vulnerability in xwcreate/gwind
    HPSBUX9409-017 Security Vulnerability in CORE-DIAG fileset
    HPSBUX9408-000 Sum and MD5 sums of HP-UX Security Bulletins
    HPSBUX9408-016 Patch sums and the MD5 program
    HPSBUX9407-015 Xauthority problem
    HPSBUX9406-014 Patch file permissions vulnerability
    HPSBUX9406-013 vhe_u_mnt allows unauthorized root access
    HPSBUX9405-011 Security Vulnerability in HP GlancePlus
    HPSBUX9405-009 PROBLEM:  Incomplete implementation of OSF/AES standard
    HPSBUX9405-010 ftpd: SITE CHMOD / race condition vulnerability
    HPSBUX9405-012 Security vulnerability in Multimedia Sharedprint
    HPSBUX9404-007 HP-UX does not have ftpd SITE EXEC vulnerability
    HPSBUX9404-008 Security Vulnerability in Vue 3.0
    HPSBUX9402-006 Security Vulnerability in DCE/9000
    HPSBUX9402-005 Security Vulnerability in Hpterm
    HPSBUX9402-004 Promiscuous mode network interfaces
    HPSBUX9402-003 Security Vulnerability in Subnetconfig
    HPSBUX9312-002 Security Vulnerability in Xterm
    HPSBUX9311-001 Security Vulnerability in Sendmail

If you would like to obtain a list of additional files available via the HP SupportLine mail service, send the following in the TEXT PORTION OF THE MESSAGE to support@support.mayfield.hp.com:

> send file_list

To get the newest security patch list:

> send security_info_list

To get the most current security patches for each version of OS:

> send hp-ux_patch_matrix

HP-patches and patch-information are available by WWW:

1. with URL http://support.mayfield.hp.com/slx/html/ptc_hpux.html http://support.mayfield.hp.com/slx/html/ptc_get.html

2. or by appending the following lines to your $HOME/.mosaic-hotlist-default and using the --> navigate --> hotlist option.

HP has a list of checksums for their security patches. Highly recommended you always compare patches with the checksum for corruption and trojans.

### NEXT

There are some security patches on ftp.next.com:/pub/NeXTanswers/Files/Patches

> SendmailPatch.23950.1
> RestorePatch.29807.16

ftp.next.com:/pub/NeXTanswers/Files/Security contains some security advisories.

Be sure to check for Rexd and uuencode alias.

### SCO Unix

Current releases of SCO UNIX (3.2v4.2) and Open Desktop (3.0) has the following security patches available:

> uod368b -- passwd
> oda377a -- xterm, scoterm, scosession, clean_screen

These can be downloaded from ftp.sco.com:/SLS. First get the file "info" which lists the actual filenames and descriptions of the supplements.

Security problems were made aware by 8LGM in the following programs for SCO:

- at(C)
- login(M)
- prwarn(C)
- sadc(ADM)
- pt_chmod

These programs, which allowed regular users to become SuperUser (root), affect the following SCO Products:

- SCO Unix System V/386 Release 3.2 Versions 4.2, 4.1, and 4.0
- SCO Open Desktop Lite Release 3.0
- SCO Open Desktop Release 3.0 and 2.0
- SCO Open Server Network System Release 3.0
- SCO Open Server Enterprise System Release 3.0

You need the following patches which are available at ftp.sco.com:/SSE:

         Binary             Patch
         ------             ------
         at(C)              sse001
         login(M)           sse002
         prwarn(C)          sse003
         sadc(ADM)          sse004
         pt_chmod           sse005

To contact SCO, send electronic mail to support@sco.com.

### Sun Microsystems, Inc. SunOS 4.x and Solaris 2.x

Patches may be obtained via anonymous ftp from ftp.uu.net:/systems/sun/sun-dist or from local Sun Answer Centers worldwide. Sun makes lists of recommended patches (including security patches) available to customers with support contracts via its Answer Centers and the SunSolve service. The lists are uploaded on an informal basis to the ftp.uu.net patch repository maintained by Sun for other customers, and posted periodically on the comp.security.unix newsgroup.

Patches are also available via anonymous ftp from sunsolve1.sun.com:/pub/patches online.sunsolve.sun.co.uk:/pub/patches/

Check out the the sunsolve www-page at http://online.sunsolve.sun.co.uk/

Below is a list of security patches that should be implemented. Please use Sun's patch list for the authoritative answer. If you see any discrepencies please notify Christopher Klaus (cklaus@iss.net).

    100075-12       rpc.lockd jumbo patch for SunOS 4.1.3
    101817-01       rpc.lockd jumbo patch for SunOS 4.1.x, x<3 (same as 10075-11).
    100103-11	script to change file permissions to a more secure mode
    100170-10	jumbo-patch ld-1.144 shared LD_LIBRARY_PATH -Bstatic SPARCworks
    100173-09	NFS Jumbo Patch
    100178-08	netd "broken server detection" breaks on fast machines
    100249-09	automounter jumbo patch
    100272-07	security hole in utmp writable
    100283-03	in.routed mishandles gateways, multiple routes
    100296-04       rpc.mountd exports to the world
    100305-14       lpr package
    100338-05	system crashes with assertion failed panic.(may be obsolete)
    100342-03	NIS client needs long recovery time if server reboots
    100359-06	streams jumbo patch
    100383-06       rdist can be used to get root access
    100421-03       rpc.rexd does not log appropriate accounting messages
    100448-01       loadmodule
    100482-04       ypxfrd exporting NIS maps to everybody
    100507-04	tmpfs jumbo patch
    100527-03	rsh uses old-style selects instead of 4.0 selects
    100536-02	NFS can cause panic: assertion failed crashes
    100557-02	ftp Jumbo patch
    100564-07	C2 Jumbo patch
    100567-04	mfree panic due to mbuf being freed twice
    100593-03	security hole in utmp writable
    100623-03	UFS jumbo patch
    100909-02	security hole in utmp writable
    101480-01	security hole in utmp writable
    101481-01	security hole in utmp writable
    101482-01	security hole in utmp writable
    102060-01       Fixes the passwd -F hole.
    101436-08       Fix for /bin/mail

Solaris 2.2 Recommended Patches:

    100982-03  SunOS 5.2: fixes for kernel/fs/fifofs
    100992-03  SunOS 5.2: streams related panics involving local transport
    100999-71  SunOS 5.2: kernel jumbo patch
    101014-05  SunOS 5.2: fixes for usr/lib/libsocket
    101022-06  SunOS 5.2: NIS/NIS+ jumbo patches
    101025-14  SunOS 5.2: Jumbo patch fixes for lp system
    101031-02  SunOS 5.2: file descriptor limit is too low on inetd
    101090-01  SunOS 5.2: fixes security hole in expreserve
    101096-02  SunOS 5.2: fixes for rpcbind
    101109-04  SunOS 5.2: fixes problems with ldterm, ptm, pts
    101122-07  SunOS 5.2: fixes for the packaging utilities
    101301-03  SunOS 5.2: security bug & tar fixes
    101348-01  SunOS 5.2: system hangs due to mblk memory leak

Solaris 2.3 Recommended Patches:

    101317-11  SunOS 5.3: lp jumbo patch
    101318-59  SunOS 5.3: Jumbo patch for kernel (includes libc, lockd)
    101327-08  SunOS 5.3: security and miscellaneous tar fixes
    101331-05  SunOS 5.3: fixes for package utilities
    101344-11  SunOS 5.3: Jumbo NFS patch security
    101347-02  SunOS 5.3: fixes for ttcompat
    101615-02  SunOS 5.3: miscellaneous utmp fixes
    101631-02  SunOS 5.3: kd and ms fixes
    101712-01  SunOS 5.3: uucleanup isn't careful enough when sending mail
    102034-01  SunOS 5.3: portmapper security hole
    101889-03  OpenWindows 3.3: filemgr forked executable ff.core has a se

Solaris 2.4 Recommended Patches:

    101945-13  SunOS 5.4: jumbo patch for kernel
    101959-02  SunOS 5.4: lp jumbo patch
    101981-01  SunOS 5.4: SECURITY: su can display root password in the co
    102007-01  SunOS 5.4: vnode v_count is not maintained correctly
    102044-01  SunOS 5.4: bug in mouse code makes "break root" attack poss
    102070-01  SunOS 5.4: Bugfix for rpcbind/portmapper

Sendmail patches are important. Check out Sendmail section.

Turn off IP-Forward on SunOs Kernel and kmem via:

> "echo ip_forwarding/W 0" | adb -w /vmunix /dev/kmem

To turn off source routed packets on Solaris 2.X. Edit /etc/rc.2.d/S69.inet and change

> ndd -set /dev/ip ip_forwarding 0
> ndd -set /dev/ip ip_ip_forward_src_routed 0

reboot.

Source routing patch for SunOs 4.1.x ftp.greatcircle.com:/pub/firewalls/digest/v03.n153.Z

To Secure a Sun console physically:
(for desktop sparc models)

> $su
> #eeprom security-mode=command
> Password:
> Retype password:
> #

(for other models)

> $su
> #eeprom secure=command
> Password:
> Retype password:
> #

This restricts access to the new command mode.

Remove suid from crash, devinfo. These both are known to be exploitable on some Sun and are rarely used.
The following is a package of patches for SunOs from Australian group SERT: ftp.sert.edu.au:/security/sert/tools/MegaPatch.1.7.tar.Z

#### Solaris 2.x Patches

Here are some file permission problems that exist on Solaris 2.3 and maybe exist on Solaris 2.4 that you should check and correct. Many file permission problems are fixed with a fix-mode module in the auto-install package:

ftp.fwi.uva.nl:/pub/solaris/auto-install/* .

After each patch installation, you will need to re-run the fix-mode.

1. Problem: As distributed, /opt/SUNWdxlib contains many _world_ writeable files, including executables. A trojan may be inserted into an executable by any user allowing them access to the accounts of anyone executing it.

   Solution:

   > "find /opt/SUNWdxlib -exec chmod go-w {} \;"

   Fix-modes will do a better job correcting permissions. You can do a simple check for trojans with:

   > "pkgchk SUNWdxlib".

2. Problem: By default, /var/nis/{hostname}.dict is _world_ writeable. "man -s4 nisfiles" says "This file is a dictionary that is used by the NIS+ database to locate its files." A quick look at it will show things like "/var/nis/{hostname}/passwd.org_dir". By changing this to, say, "/tmp/{hostname}/passwd.org_dir", it _may_ be possible to replace the NIS+ password (or any arbitrary) map with a bogus one. There are also many files in /var/nis/{hostname} that are world writeable. However, since /var/nis/{hostname} is root owned, mode 700, this shouldn't be a problem. It also shouldn't be necessary. All the files in /var/nis/{hostname} are world readable which is not a good way to have shadow passwords.

   Solution: By putting a "S00umask.sh" with contents "umask 022" in each /etc/rc?.d it will make sure that all daemons will start with an umask of 022.

   The default umask really should be 022, not 0.

   "strings /var/nis/{hostname}.dict" to make sure all the paths are sane, then to correct permissions:

   > "chmod 644 /var/nis/{hostname}.dict"
   > "chmod 700 /var/nis/{hostname}"
   > "chmod 600 /var/nis/{hostname}/*"

3. Problem: /etc/hostname.le0 is _world_ writeable. This allows anyone to change the address of the ethernet interface.

   Solution:

   > "chmod 644 /etc/hostname.le0"

4. Problem: /var/statmon, /var/statmon/sm, and /var/statmon/sm.bak are _world_ writeable directories. They are used by statd to "provide the crash and recovery functions for the locking services of NFS. You could trick an NFS client into thinking a server crashed.

   Solution:

   > "find /var/statmon -exec chmod o-w {} \;"

5. Problem: The following files are _world_ writeable:

   > /var/adm/vold.log
   > /var/log/syslog*
   > /var/lp/logs/lpsched
   > /var/lp/logs/lpNet
   > /etc/mnttab
   > /etc/path_to_inst.old
   > /var/saf/_log
   > /etc/rmtab

   Solution: It may not be possible to tighten up permissions on all the world writeable files out there without breaking something. However, it'd be a good idea to at least know what they are. Something like:

   > "find / -user root \( -type d -o -type f \) -perm -2 -ls"

   will at least let you know which files may contain bogus information. Checking for other than root, bin, sys, lp, etc. group writeable files would be a good idea as well.

6. Problem: Solaris still ships /usr/kvm/crash mode 2755 which allows anyone to read kmem.

   Solution: Change permission to 0755.

7. Problem: /etc, /usr/ and /usr/sys may have mode 775 which allows groups to write over files.

   Solution: Change permissions to 755.

### SGI

ftp.sgi.com and sgigate.sgi.com have a "/security" directory.

{3.3,4.0,5.0} including sendmail and lpr. lpr allowed anyone to get root access.

Patch65 and patch34 correct vulnerability in SGI help system which enabled users to gain root priviledges.

                    Standard      System V       MD5
                    Unix          Unix           Digital Signature
    patch34.tar.Z:  11066 15627   1674 31253     2859d0debff715c5beaccd02b6bebded
    patch65.tar:    63059 1220    15843 2440     af8c120f86daab9df74998b31927e397

Check for the Following: Default accounts with no passwords: 4DGifts, lp, nuucp, demos, tutor, guest, tour

To Disable IP_Forwarding on SGI:
edit /usr/sysgen/master.d
change int ipforwarding = 1 to 0;
then recompile kernel by autoconfig -f; for IRIX 4.0.5

Remove suid from /usr/sbin/colorview
Remove suid from /usr/lib/vadmin/serial_ports on Irix 4.X
Remove suid from /usr/lib/desktop/permissions
Remove suid from /usr/bin/under

/usr/etc/arp is setgid sys in IRIX up to and including 5.2, allowing anyone who can log into your machine to read files which should be readable only by group 'sys'.
Remove suid from /usr/sbin/cdinstmgr
Remove suid from /etc/init.d/audio
chmod g-w /usr/bin/newgrp

/usr/sbin/printers has a bug in IRIX 5.2 (and possibly earlier 5.x versions) which allows any user to become root.

/usr/sbin/sgihelp has a bug in IRIX 5.2 (and possibly earlier 5.x versions) which allows any user to become root. This is so bad that the patch is FTPable from ftp.sgi.com:/security/, and SGI is preparing a CD containing only that patch.

The version of inst which comes with patch 34, which is required for installation of all other patches (even those with lower numbers) saves old versions of binaries in /var/inst/patchbase. It does not remove execution or setuid permissions.

Irix has many built-in security knobs that you should know how to turn them on.

    Manpage                 Things to look for
    -------         ---------------------------------------------------

    login           setup /etc/default/login to log all attempts with
                    SYSLOG=ALL, add support for external authentication
                    programs with SITECHECK=/path/to/prog

    portmap         use '-a  mask,match' to restrict most of the portmap
                    services to a subset of hosts or networks
                    use '-v' to log all unprivileged accesses to syslog

    rshd            use '-l' to disable validation using .rhosts files
                    use '-L' to log all access attempts to syslog

    rlogind         use '-l' to disable validation using .rhosts files
                    (beware, this was broken prior to IRIX 5.3)

    fingerd         use '-l' to log all connections
                    use '-S' to suppress information about login status,
                    home directory, and shell
                    use '-f msg-file' to make it just display that file

    ipfilterd       IP packet filtering daemon

## Part 3 - Particular Vulnerabilities

### Ftp

Check the Sendmail Patches

#### IBM Corporation

A possible security exposure exists in the bos.obj sendmail subsystem in all AIX releases.

The user can cause arbitrary data to be written into the sendmail queue file. Non-privileged users can affect the delivery of mail, as well as run programs as other users.

Workaround

A. Apply the patch for this problem. The patch is available from software.watson.ibm.com. The files will be located in the /pub/aix/sendmail in compressed tar format. The MD5 checksum for the binary file is listed below, ordinary "sum" checksums follow as well.

               File            sum             MD5 Checksum
               ----            ---             ------------
               sendmail.tar.Z 35990           e172fac410a1b31f3a8c0188f5fd3edb

B. The official fix for this problem can be ordered as Authorized Program Analysis Report (APAR) IX49257

To order an APAR from IBM in the U.S. call 1-800-237-5511 and ask for shipment as soon as it is available (in approximately two weeks). APARs may be obtained outside the U.S. by contacting a local IBM representative.

#### Motorola Computer Group (MCG)

The following MCG platforms are vulnerable:

> R40
> R32 running CNEP add-on product
> R3 running CNEP add-on product

The following MCG platforms are not vulnerable:

> R32 not including CNEP add-on product
> R3 not including CNEP add-on product
> R2
> VMEEXEC
> VERSADOS

The patch is available and is identified as "patch_43004 p001" or "SCML#5552". It is applicable to OS revisions from R40V3 to R40V4.3. For availability of patches for other versions of the product contact your regional MCG office at the numbers listed below.

Obtain and install the appropriate patch according to the instructions included with the patch.

The patch can be obtained through anonymous ftp from ftp.mcd.mot.com [144.191.210.3] in the pub/patches/r4 directory. The patch can also be obtained via sales and support channels. Questions regarding the patch should be forwarded to sales or support channels.

For verification of the patch file:

            Results of      sum -r  == 27479 661
                            sum     == 32917 661
                            md5     == 8210c9ef9441da4c9a81c527b44defa6

Contact numbers for Sales and Support for MCG:

> United States (Tempe, Arizona)
> Tel: +1-800-624-0077
> Fax: +1-602-438-3865

> Europe (Brussels, Belgium)
> Tel: +32-2-718-5411
> Fax: +32-2-718-5566

> Asia Pacific / Japan (Hong Kong)
> Tel: +852-966-3210
> Fax: +852-966-3202

> Latin America / Australia / New Zealand (U.S.)
> Tel: +1 602-438-5633
> Fax: +1 602-438-3592

#### Open Software Foundation

The local vulnerability described in the advisory can be exploited in OSF's OSF/1 R1.3 (this is different from DEC's OSF/1). Customers should apply the relevant portions of cert's fix to their source base. For more information please contact OSF's support organization at osf1-defect@osf.org.

#### The Santa Cruz Operation

SCO systems are not vulnerable to the IDENT problem. Systems running the MMDF mail system are not vulnerable to the remote or local problems.

The following releases of SCO products are vulnerable to the local problems.

> SCO TCP/IP 1.1.x for SCO Unix System V/386 Operating System Release 3.2
> Versions 1.0 and 2.0
> SCO TCP/IP 1.2.x for SCO Unix System V/386 Operating System Release 3.2
> Versions 4.x
> SCO TCP/IP 1.2.0 for SCO Xenix System V/386 Operating System Release 2.3.4

> SCO Open Desktop Lite Release 3.0
> SCO Open Desktop Release 1.x, 2.0, and 3.0
> SCO Open Server Network System, Release 3.0
> SCO Open Server Enterprise System, Release 3.0

Patches are currently being developed for the release 3.0 and 1.2.1 based products. The latest sendmail available from SCO, on Support Level Supplement (SLS) net382d, is also vulnerable.

Contacts for further information:

e-mail: support@sco.COM

USA, Canada, Pacific Rim, Asia, Latin America 6am-5pm Pacific Daylight Time (PDT)

1-408-425-4726 (voice)
1-408-427-5443 (fax)

Europe, Middle East, Africa: 9am-5:30pm British Standard Time (BST)

+44 (0)923 816344 (voice)
+44 (0)923 817781 (fax)

#### Sequent Computer Systems

Sequent customers should contact Sequent Customer Service and request the Fastpatch for sendmail.

phone: 1-800-854-9969.
e-mail: service-question@sequent.com

#### Silicon Graphics, Inc.

At the time of writing of this document, patches/binaries are planned for IRIX versions 4.x, 5.2, 5.3, 6.0, and 6.0.1 and will be available to all SGI customers.

The patches/binaries may be obtained via anonymous ftp (ftp.sgi.com) or from your support/service provider.

On the anonymous ftp server, the binaries/patches can be found in either ~ftp/patches or ~ftp/security directories along with more current pertinent information.

For any issues regarding this patch, please, contact your support/service provider or send email to cse-security-alert@csd.sgi.com .

#### Sony Corporation

            NEWS-OS 6.0.3   vulnerable; Patch SONYP6022 [sendmail] is available.
            NEWS-OS 6.1     vulnerable; Patch SONYP6101 [sendmail] is available.
            NEWS-OS 4.2.1   vulnerable; Patch 0101 [sendmail-3] is available.
                            Note that this patch is not included in 4.2.1a+.

Patches are available via anonymous FTP in the /pub/patch/news-os/un-official directory on ftp1.sony.co.jp [202.24.32.18]:

            4.2.1a+/0101.doc        describes about patch 0101 [sendmail-3]
            4.2.1a+/0101_C.pch      patch for NEWS-OS 4.2.1C/a+C
            4.2.1a+/0101_R.pch      patch for NEWS-OS 4.2.1R/RN/RD/aRD/aRS/a+R

            6.0.3/SONYP6022.doc     describes about patch SONYP6022 [sendmail]
            6.0.3/SONYP6022.pch     patch for NEWS-OS 6.0.3

            6.1/SONYP6101.doc       describes about patch SONYP6101 [sendmail]
            6.1/SONYP6101.pch       patch for NEWS-OS 6.1

            Filename                BSD             SVR4
                                    Checksum        Checksum
            --------------          ---------       ---------
            4.2.1a+/0101.doc        55361 2         19699 4
            4.2.1a+/0101_C.pch      60185 307       25993 614
            4.2.1a+/0101_R.pch      35612 502       31139 1004
            6.0.3/SONYP6022.doc     03698 2         36652 4
            6.0.3/SONYP6022.pch     41319 436       20298 871
            6.1/SONYP6101.doc       40725 2         3257 3
            6.1/SONYP6101.pch       37762 434       4624 868

            MD5 checksums are:
            MD5 (4.2.1a+/0101.doc) = c696c28abb65fffa5f2cb447d4253902
            MD5 (4.2.1a+/0101_C.pch) = 20c2d4939cd6ad6db0901d6e6d5ee832
            MD5 (4.2.1a+/0101_R.pch) = 840c20f909cf7a9ac188b9696d690b92
            MD5 (6.0.3/SONYP6022.doc) = b5b61aa85684c19e3104dd3c4f88c5c5
            MD5 (6.0.3/SONYP6022.pch) = 1e4d577f380ef509fd5241d97a6bcbea
            MD5 (6.1/SONYP6101.doc) = 62601c61aef99535acb325cf443b1b25
            MD5 (6.1/SONYP6101.pch) = 87c0d58f82b6c6f7811750251bace98c

If you need further information, contact your vendor.

#### Solbourne

Grumman System Support Corporation now performs all Solbourne software and hardware support. Please contact them for further information.

e-mail: support@nts.gssc.com
phone: 1-800-447-2861

#### Sun Microsystems, Inc.

Sun has developed patches for all supported platforms and architectures, including Trusted Solaris, Solaris x86, and Interactive Unix. Note that Sun no longer supports the sun3 architecture and versions of the operating system that precede 4.1.3.

Current patches are listed below.

             OS version      Patch ID    Patch File Name
             ----------      ---------   ---------------
             4.1.3           100377-19   100377-19.tar.Z
             4.1.3_U1        101665-04   101665-04.tar.Z
             5.3             101739-07   101739-07.tar.Z
             5.4             102066-04   102066-04.tar.Z
             5.4_x86         102064-04   102064-04.tar.Z

The patches can be obtained from local Sun Answer Centers and through anonymous FTP from ftp.uu.net in the /systems/sun/sun-dist directory. In Europe, the patches are available from mcsun.eu.net in the /sun/fixes directory.

The patches are also available through the usual URL on World Wide Web.

Sun is issuing Security Bulletin #129 with details on February 22; the patches will become available worldwide during the 24 hours to follow.

### HTTPd (WWW)

There is a bug in NCSA v1.3 HTTP Web server that allows anyone to execute commands remotely. The bug is due to overwriting a buffer. Please get the newest patch from ftp.ncsa.uiuc.edu. More information is available from http://hoohoo.ncsa.uiuc.edu/docs/patch_desc.html .

### Rdist Patches

(Unless you really need rdist, chmod 000 rdist works fine.)

Apollo Domain/OS SR10.3 and SR10.3.5 (Fixed in SR10.4)
a88k PD92_P0316
m68k PD92_M0384

Cray Research, Inc. UNICOS 6.0/6.E/6.1 Field Alert #132 SPR 47600

IBM RS/6000 AIX levels 3005, 2006, 2007, and 3.2 apar ix23738
Patches may be obtained by calling Customer Support at 1-800-237-5511.

NeXT Computer, Inc. NeXTstep Release 2.x
Rdist available on the public NeXT FTP archives.

Silicon Graphics IRIX 3.3.x/4.0 (fixed in 4.0.1) Patches may be obtained via anonymous ftp from sgi.com in the sgi/rdist directory.

Solbourne OS/MP 4.1A Patch ID P911121003

Sun Microsystems, Inc. SunOS 4.0.3/4.1/4.1.1 Patch ID 100383-06

### IP Spoofing Vulnerabilities

IP Spoofing attacks allow an intruder to send packets as if they were coming from a trusted host and some services based on IP based authenication allow an intruder to execute commands. Because these packets appear to come from a trusted host, it may be possible to by-pass firewall security. IP Spoofing is more detailed in the following papers:

- "Security Problems in the TCP/IP Protocol Suite" by Steve Bellovin. It is available for ftp from research.att.com:/dist/internet_security/ipext.ps.Z

- "A Weakness in the 4.2BSD Unix TCP/IP Software," by Robert T. Morris. It is available for ftp from research.att.com:/dist/internet_security/117.ps.Z

Some of the services based on IP authenication are:

- Rsh
- Rlogin
- NFS
- NIS
- X Windows
- Services secured by TCP Wrappers access list.

It can help turn off these services especially Rsh and Rlogin.

You can filter out IP spoofed packets with certian routers with the use of the input filter. Input filter is a feature on the following routers:

- Bay Networks/Wellfleet, version 5 and later
- Cabletron with LAN Secure
- Cisco, RIS software version 9.21 and later
- Livingston
- NSC

TCP Wrapper in conjunction with Identd can help to stop IP spoofing because then the intruder must not not only spoof the connection to Rsh/Rlogin, they must spoof the information to identd which is not as trivial.

TCP Wrapper is available on ftp.win.tue.nl:/pub/security/tcp_wrappers_6. 3.shar.Z

Identd is available on ftp.lysator.liu.se:/pub/ident/servers

Add the following to TCP Wrappers access list:

> ALL: UNKNOWN@ALL: DENY

This will drops all TCP connections where ident lookup fails.

### Hijacking terminal connections

Intruders are using a kernel module called TAP that initially was used for capturing streams which allows you to view what a person is typing. You can use it to write to someone's steam, thus emulating that person typing a command and allowing an intruder to "hijack" their session.

Tap is available on ftp.sterling.com /usenet/alt.sources/volume92/Mar in the following files:

- 920321.02.Z TAP - a STREAMS module/driver monitor (1.1)
- 920322.01.Z TAP - a STREAMS module/driver monitor (1.5) repost
- 920323.17.Z TAP - BIG BROTHERS STREAMS TAP DRIVER (1.24)

An intruder needs to install TAP as root. Therefore if you have installed all patches and taken the necessary precautions to eliminate ways to obtain root, the intruder has less chance of installing TAP. You can disable loadable modules on SunOs 4.1.x by editing the kernel configuraion file found in /sys/`arch -k`/conf directory and comment out the following line with a "#" character:

> options VDDRV # loadable modules

Then build and install the new kernel:

> # /etc/config CONFIG_NAME
> # cd ../CONFIG_NAME
> # make
> # cp /vmunix /vmunix.orig
> # cp vmunix /
> # sync; sync; sync

Reboot the system to activate the new kernel. You can also try to detect the Tap program by doing the following command:

> modstat

Modstat displays all loaded modules. An intruder could trojan modstat as well therefore you may want to verify the checksum of modstat.

## Part 4 - Unpatched Vulnerabilities

This is intended to let consumers know that these holes have already been fully disclosed and everyone already knows about it. These are the vulnerabilities that vendors are suppose to be releasing patches for ASAP. Hopefully this list will stay short and small.

    Vendor          Bug                 Result
    Sun5.x          no promisc flags    Can not tell if machine is sniffing

### Acknowledgements

I would like to thank the following people for the contribution to this FAQ that has helped to update and shape it:

- Jonathan Zanderson (jsz@ramon.bgu.ac.il)
- Rob Quinn <rjq@phys.ksu.edu>
- Dr.-Ing. Rudolf Theisen, <r.theisen@kfa-juelich.de>
- Gerald (Jerry) R. Leslie <jleslie@dmccorp.com>
- Walker Aumann (walkera@druggist.gg.caltech.edu)
- Chris Ellwood (cellwood@gauss.calpoly.edu)
- Dave Millar (millar@pobox.upenn.edu)
- Paul Brooks (paul@turbosoft.com.au)

### Copyright

    This paper is Copyright (c) 1994, 1995
       by Christopher Klaus of Internet Security Systems, Inc.

Permission is hereby granted to give away free copies electronically. You may distribute, transfer, or spread this paper electronically. You may not pretend that you wrote it. This copyright notice must be maintained in any copy made. If you wish to reprint the whole or any part of this paper in any other medium excluding electronic medium, please ask the author for permission.

### Disclaimer

The information within this paper may change without notice. Use of this information constitutes acceptance for use in an AS IS condition. There are NO warranties with regard to this information. In no event shall the author be liable for any damages whatsoever arising out of or in connection with the use or spread of this information. Any use of this information is at the user's own risk.

### Address of Author

Please send suggestions, updates, and comments to:

### Internet Security Systems, Inc.

Internet Security Systems, Inc, located in Atlanta, Ga., specializes in the developement of security scanning software tools. Its flagship product, Internet Scanner, is software that learns an organization's network and probes every device on that network for security holes. It is the most comprehensive "attack simulator" available, checking for over 100 security vulnerabilities.