CERT^® Advisory CA-1997-01 Multi-platform Unix FLEXlm Vulnerabilities

A complete revision history is at the end of this file.

The text of this advisory was originally released on September 19, 1996, as AUSCERT Advisory AA-96.03 "Multi-platform Unix FLEXlm Vulnerabilities," developed by Australian Computer Emergency Response Team. Because of the seriousness of the problem, we are reprinting the AUSCERT advisory here with their permission. Only the contact information at the end has changed: AUSCERT contact information has been replaced with CERT/CC contact information.

We will update this advisory as we receive additional information. Look for it in an "Updates" section at the end of the advisory.

AUSCERT has received information concerning several problems involving the use of the FLEXlm licence management package on Unix systems. FLEXlm is used by many vendors to licence their products, and is supplied to them by GLOBEtrotter Software (previously, it was supplied by Highland Software). Many vendors have misconfigured the FLEXlm system to run as the root user, and some versions of the FLEXlm licence management daemon lmgrd contain a security vulnerability. These problems may allow local users to create users to create arbitrary files on the system and execute arbitrary programs using the privileges of the user running the FLEXlm daemons.

System administrators are advised that the FLEXlm package may be installed as part of the installation procedures of other vendor and third-party products. Due to the way that the licence management software is often installed, it may be unnecessarily running as root making it possible to gain unauthorised privileged access.

This means that the FLEXlm package may be installed on systems and running as the root user without the knowledge of the system administrator.

Note that the vulnerabilities described here do not affect the security of the FLEXlm licences and licencing restriction. The vulnerabilities allow users to compromise security of the Operating System.

1. Description

The FLEXlm licence management package is used by many vendors to licence their products. Many vendors have misconfigured the FLEXlm system to run as the root user which opens a number of computer security vulnerabilities which can be used to compromise the Unix operating system. This is described in paragraph (a).

In addition, some versions of the FLEXlm licence management daemon lmgrd contain a security vulnerability. This is described in paragraph (b).

(a) Insecure configuration of vendor product installation

Due to some confusion in the documentation supplied to vendors using the FLEXlm package, the FLEXlm licence management software often runs with root privileges. This often occurs due to the FLEXlm daemons being started by the system initialisation scripts. If the daemons are running with root privileges they may be used by local users to gain unauthorised root privileges. This potentially affects all versions of the FLEXlm licence management daemon.

GLOBEtrotter Software advise that the FLEXlm package does not require root privileges to operate correctly. FLEXlm daemons should be started by a non-privileged user with a restrictive umask setting, limiting the associated configuration vulnerabilities.

(b) Security vulnerability in FLEXlm licence management daemon

A vulnerability has been found in the FLEXlm licence management daemon which may allow local users unauthorised access to the account running the FLEXlm licence management daemon.

This vulnerability exists in all versions of the FLEXlm licence management daemon from version 4.0 up to, and including, version 5.0a. A new version of the daemon has been made available by GLOBEtrotter Software that fixes this vulnerability. See Section 3.4.

Versions earlier than version 4.0 do not have this vulnerability. GLOBEtrotter Software advise that all existing versions of the lmgrd daemon may be updated to the most recent version (version 5.0b) without change in functionality. This version of lmgrd will work successfully with all existing FLEXlm-licensed products. See Section 3.4.

1.1 Additional Description Information

This section contains additional information on locating any FLEXlm components, determining the configuration of those components, and identifying information required for the Workarounds/Solutions in Section 3.

(a) Vendor configurations may be customised

Vendors using the FLEXlm licence management package to licence their products have the ability to customise FLEXlm to meet their own needs. This may include names, locations, and content of many files, in addition to how the software is installed and used. Therefore, care is required in locating any vulnerable software or configurations, and implementing workaround solutions.

(b) Determining if FLEXlm is installed

The FLEXlm licence management package is often installed as part of the installation procedures of other vendor and third-party products. The system administrator may not be aware that FLEXlm has been installed.

The following command run as root should determine if the FLEXlm licence management software is installed.

# find /etc -type f -exec egrep -il 'lmgrd|flexlm|licdir' {} \;

Any files listed should be investigated further to see if they relate to the FLEXlm licence management product.

In particular, it is important to locate the FLEXlm licence management initialisation files (the files where FLEXlm licence management daemons are started from) as these will become important when discussing the Workarounds/Solutions in Section 3.

(c) Determining the version of the FLEXlm licence management daemon(s)

The version of the FLEXlm licence management daemon can be determined by examining the strings(1) output of the binary daemon and searching for the strings "Copyright" and "FLEXlm".

For example:

# strings /usr/local/flexlm/licences/lmgrd | grep -i copyright | grep -i flexlm

Note that more than one version of the FLEXlm licence management daemon may be executing, depending on what products are installed.

The version number is also written to stdout (which may have been redirected to a log file) when the licence management daemon is started.

(d) Identifying the user running the FLEXlm licence management daemons

The licence management daemon is often called "lmgrd" or some derivative containing the string "lmgrd" (for example, lmgrd.abc). On some products, the name of the licence management daemon may have been changed to an arbitrary name (for example, lm_ABC4.ld). It should be possible to locate most running versions of the licence management daemon by examining the files identified in Section 1.1(b) or by using one of the following commands (Note this may locate other processes not related to FLEXlm, and may not locate all FLEXlm related processes):

% ps -auxww | grep -i lm | grep -v grep
#BSD systems

% ps -ef | grep -i lm | grep -v grep
# SYS V systems

If any licence management daemon is running as the root user, then a number of vulnerabilities exist as the daemon was not designed to be run with root privileges.

Note that more than one FLEXlm licence management daemon may be running depending on what products have been installed. It is important to check for all running versions of the daemon.

(e) Locating the licence management files

Each licence management daemon has an associated licence file. The licence file is usually specified by the "-c" option on the command line, the LM_LICENSE_FILE environment variable, or is found in the default location /usr/local/flexlm/licenses/license.dat. The licence file describes which products the daemon is administering and the location of associated daemons. The licence files become important when discussing the Workarounds/Solutions in Section 3.

2. Impact

Any versions of the FLEXlm licence management daemons executing using a system account (for example, bin, daemon, sys) or a privileged account (such as root) may allow local users to create or overwrite arbitrary files on the system. This may be leveraged to gain root access.

FLEXlm licence management daemons containing the security vulnerability (indicated in Section 1(b)) may allow local users unauthorised access to the account running the daemons.

Information on gaining unauthorised access to Unix systems using the FLEXlm Licence Management software has been widely distributed.

3. Workarounds/Solution

Note that all four (4) sections should be reviewed and implemented if appropriate. Each section addresses a different problem.

After the installation of ANY product or upgrade, the system must be checked to verify if a FLEXlm licence management daemon has been added. If a FLEXlm licence management daemon has been added, then Sections 3.1 to 3.4 of this Advisory should be applied to it to ensure a more secure configuration.

3.1 Run as a non-privileged user

GLOBEtrotter Software advise that the FLEXlm licence management software does not require root privileges to operate. The FLEXlm licence management daemon should be run by a non-privileged user.

If the licence management daemon is executing with root or some other system account permissions (such as bin, sys, daemon or any other system account), it must be modified to use a non-privileged user.

If the licence management daemon is already executing as a non-privileged user, then the remainder of Section 3.1 may be skipped.

It is recommended that a new user "flexlm" be created for the specific purpose of running the FLEXlm licence management daemon. In this case, Steps 3.1.1 through 3.1.5 should be followed.

3.1.1 Create a non-privileged account for use by FLEXlm.

For example:

flexlm:*:2000:250:FLEXlm Licence Manager:/nonexistent:/bin/sh

Note the account must have the following properties:

.password set to '*' as interactive access is not required
.a unique userid (the 2000 is only an example)
.a unique groupid (the 250 is only an example)
.a shell of /bin/sh

The following instructions refer to this account as the "flexlm user". If the FLEXlm daemons were already running as a non-privileged user, then this will be the "flexlm user" below.

3.1.2 Locate the licence file(s).

These may be identified in one of three ways:
. specified by the "-c" option to the FLEXlm licence daemons
. specified by the LM_LICENSE_FILE environment variable
. located in the default location: /usr/local/flexlm/licenses/license.dat

Note that there is always a single licence file for each licence daemon, but there may be more than one licence daemon running on a system.

3.1.3 The licence management daemons must use a non-privileged TCP port for communication. The port number chosen may be arbitrary, but all clients must be configured to use the same port.

The port is specified in the licence data file on the SERVER line. It is the fourth (4th) field on this line. For example:

SERVER xyzzy 123456789 1234

the port number is 1234.

3.1.4 Locate where the FLEXlm licence management daemon is started.

This is often in the system startup scripts, but may not exclusively be so. An example startup line is:

$licdir/$lmgrd -c $licdir/$licfile >> /tmp/license_log 2>&1 &

Logging information is written to stdout by the daemons, and is often redirected to a log file when the daemon is started.

3.1.5 Modify the line in the FLEXlm startup files that starts the licence management daemon to look similar to the following:

su flexlm -c "{original command line in startup file}"

where flexlm is the user created in Step 3.1.1. Note that the logging information that is written to stdout from the daemon should not be written to files in /tmp or other world writable directories, but to a specially created directory that the flexlm user can write log information to.

For example:

su flexlm -c "$licdir/$lmgrd -c ... >> /var/log/flexlm/license_log 2>&1 &"

3.2 File Ownership

Regardless of which user is executing the FLEXlm licence management software, additional security vulnerabilities may allow a user to gain unauthorised access to the account running the daemon or engage in denial of service attacks by deleting files.

These vulnerabilities may be limited if you ensure that no files on the system are owned or are writable by the flexlm user. The possible exception to this requirement is log files (see Section 3.1.4) and temporary files. All licence and FLEXlm executable files must be readable or executable by the flexlm user. Additional daemons required by the FLEXlm licence management daemon are specified in the licence data files (located in Section 3.1.2) on the DAEMON line.

These file ownership and mode changes should be done for all versions of FLEXlm.

Note that some vendors may have installed the FLEXlm software owned by the flexlm user. This configuration should be modified as detailed in this section.

3.3 umask Setting

The FLEXlm licence management daemons inherit the umask setting from the environment in which they are started. When FLEXlm is started as part of the system initialisation procedures, the umask is inherited from init(1M) and is usually set to 000. The FLEXlm licence management daemons inherit the umask setting from the environment in which they are started. When FLEXlm is started as part of the system initialisation procedures, the umask is inherited from init(1M) and is usually set to 000. This means that FLEXlm will open files which are world and group writable. A more appropriate umask setting is 022.

This should be done for all versions of FLEXlm.

The umask can be set in the FLEXlm startup files which were identified in Section 3.1.4. This should be the first command executed in the startup script for FLEXlm licence management daemons.
For example:

#!/bin/sh
umask 022 # add this line here rest of the FLEXlm startup file

3.4 Vendor Patch for Vulnerability

GLOBEtrotter Software have made a new version of the FLEXlm licence management daemon (version 5.0b) available which rectifies the reported vulnerability in Section 1(b).

All versions of the FLEXlm licence management daemon from version 4.0 up to, and including, version 5.0a should be upgraded immediately.

GLOBEtrotter Software advise that all versions of the FLEXlm lmgrd may be upgraded to the latest version (version 5.0b) without loss of existing functionality. This version of lmgrd will work successfully with all existing FLEXlm-licensed products.

Note that there may be more than one copy of FLEXlm's lmgrd on your system that requires upgrading, depending on what products are installed. The existing licence management daemon(s) should be replaced with the new version, but the location and file name of the version you are replacing should be preserved.

Version 5.0b of the FLEXlm licence management daemon may be found at

http://www.globetrotter.com/lmgrd.htm

MD5 (alpha_u1/lmgrd) = 40ec89f3c9cfcdecfaa442d59db179e1
MD5 (decs_u4/lmgrd) = 0cd60373d0f0bef8f7a2de290306490b
MD5 (hal_u5/lmgrd) = 1e678c62d6346480c6ce097df1a6c708
MD5 (hp300_u8/lmgrd) = ffbdf1c581fd383ca01ba239230f2964
MD5 (hp700_u8/lmgrd) = f972b3a449cd57e8d472a0394613e076
MD5 (i86_d4/lmgrd) = 37256e1abe50116c504b6d2f83a23c55
MD5 (i86_l1/lmgrd) = f1bbfdf13d1145fb3b18afb063b93ac3
MD5 (i86_x5/lmgrd) = e6623c2124205512fc9ed21bc9aee061
MD5 (ncr_u2/lmgrd) = 0919251ca4321dfaa166e008f8d34899
MD5 (nec_u2/lmgrd) = 7e1ae2664219f59e0c26b1a1d97838df
MD5 (ppc_u4/lmgrd) = d4d038cd5bdfa4c44d2523cf11461d63
MD5 (ppc_x5/lmgrd) = f1aae597d4052734b4e01cac76407cf6
MD5 (rm400_u5/lmgrd) = cb2d48efa809cbb3457f835f2db47926
MD5 (rs6000_u3/lmgrd) = fadf0fc424f1fcc11cd04fe8678b79cf
MD5 (sco_u3/lmgrd) = e288917fb8fac8fdc8f1f2a9d985eb50
MD5 (sgi_u4/lmgrd) = 0637f1dae3adb5d7a3597b6d486e18af
MD5 (sgi_u5/lmgrd) = 31f1f1d1b02917f4c9c062c33e4636a4
MD5 (sgir8_u6/lmgrd) = ba0892403ef4bebf38ad22831d3d8183
MD5 (sony_u4/lmgrd) = 032b4521333e7583afd0f783f5555522
MD5 (sun4_u4/lmgrd) = f87130d077d4d1cc8469d9818a085d33
MD5 (sun4_u5/lmgrd) = 36a2930f3dcbe92155866e7a9864b8a5

A copy of these files will be available until 31-Oct-1996 from:

ftp://ftp.auscert.org.au/pub/mirrors/ftp.globetrotter.com/flexlm/unix/

4. Additional information

4.1 User Manual and Frequently Asked Questions

GLOBEtrotter Software have a user manual that describes the FLEXlm Licence Management system which is available to all users. A FAQ (Frequently Asked Questions) document containing useful information is also available. These can be located at:

http://www.globetrotter.com/manual.htm
http://www.globetrotter.com/faq.htm

4.2 Additional Vendor Information

GLOBEtrotter Software have made available some additional information concerning these security vulnerabilities. It can be accessed at:

http://www.globetrotter.com/auscert.htm

4.3 General misconfiguration description

The misconfiguration of the FLEXlm licence management daemon is a generic problem where software that was not designed to be run with root privileges automatically gains those privileges as a result of being started by the system initialisation scripts. Only those programs that require root privileges should be run as root.
Attention is drawn to the Unix Secure Programming Checklist which addresses this issue, in addition to others. The checklist is available from:

ftp://ftp.auscert.org.au/pub/auscert/papers/secure_programming_checklist

AUSCERT thanks Peter Marelas from The Fulcrum Consulting Group, GLOBEtrotter Software, DFN-CERT, CERT/CC, and Sun Microsystems for their advice and cooperation in this matter.

UPDATES

Silicon Graphics, Inc.

The solution to this problem is to install version 3.0 of the the License Tools, license_eoe subsystem.
To determine the version of License Tools installed on a particular system, the following command can be used:

% versions license_eoe

I = Installed, R = Removed

In the above case, version 1.0 of the License Tools is installed and the steps below should be performed. If the output returned indicates "License Tools 3.0," the latest license subsystem is installed and no further action is required.

**** IRIX 4.x ****
The 4.x version of IRIX is not vulnerable as no license manager subsystems were released for this IRIX version. No action is required.

**** IRIX 5.0.x, 5.1.x, 5.2 ****
The 5.0.x, 5.1.x and 5.2 versions of IRIX are not vulnerable as no license manager subsystems were released for these IRIX versions. No action is required.

**** IRIX 5.3 ****
For the IRIX operating system version 5.3 an inst-able new version of software has been generated and made available via anonymous FTP and your service/support provider. The software is version 3.0 of the License Tools, license_eoe subsystem and will install on IRIX 5.3 only.

The SGI anonymous FTP site is sgigate.sgi.com (204.94.209.1) or its mirror, ftp.sgi.com. Software is referred to as License5.3.tar and can be found in the following directories on the FTP server:

~ftp/Security
or
~ftp/Patches/5.3

##### Checksums ####
The actual software will be a tar file containing the following files:

Filename: license_eoe
Algorithm #1 (sum -r): 01409 7 license_eoe
Algorithm #2 (sum): 56955 7 license_eoe
MD5 checksum: 38232F3DE67373875577B167B2DA2DA3

Filename: license_eoe.books
Algorithm #1 (sum -r): 33405 809 license_eoe.books
Algorithm #2 (sum): 53177 809 license_eoe.books
MD5 checksum: D1D931936AB681A7B259BD75DCA6D7F9

Filename: license_eoe.idb
Algorithm #1 (sum -r): 59742 54 license_eoe.idb
Algorithm #2 (sum): 32839 54 license_eoe.idb
MD5 checksum: 4F7EE6965539FCFEEDE07E3FFD71CF5A

Filename: license_eoe.man
Algorithm #1 (sum -r): 58166 271 license_eoe.man
Algorithm #2 (sum): 23426 271 license_eoe.man
MD5 checksum: 41946D8E27032A929350B2C27D065DE5

Filename: license_eoe.sw
Algorithm #1 (sum -r): 29827 7692 license_eoe.sw
Algorithm #2 (sum): 52617 7692 license_eoe.sw
MD5 checksum: 720EF1907DD0C3113CB4A98AD602010B

**** IRIX 6.0, 6.0.1 *****
The 6.0.x versions of IRIX are not vulnerable as no license manager subsystems were released for these IRIX versions. No action is required.

**** IRIX 6.1 ****
The license manager software provided with IRIX 6.1 is version 1.0 of the License Tools, license_eoe subsystem for IRIX 6.1. This version is not vulnerable to these security issues.

However, if an upgrade of the License Tools, license_eoe subsystem was done (see above section on determining version installed with versions command), then a security vulnerability might exist. In order to remove this vulnerability, either a downgrade to version 1.0 of the License Tools, license_eoe subsystem is required or upgrade the entire IRIX version to 6.2 and apply the version 3.0 of the License Tools, license_eoe subsystem.

**** IRIX 6.2 ****
For the IRIX operating system version 6.2 an inst-able new version of software has been generated and made available via anonymous FTP and your service/support provider. The software is version 3.0 of the License Tools, license_eoe subsystem and will install on IRIX 6.2 only.

The SGI anonymous FTP site is sgigate.sgi.com (204.94.209.1) or its mirror, ftp.sgi.com. Software is referred to as License6.2.tar and can be found in the following directories on the FTP server:

~ftp/Security
or
~ftp/Patches/6.2

##### Checksums ####

The actual software will be a tar file containing the following files:

Filename: license_eoe
Algorithm #1 (sum -r): 53638 7 license_eoe
Algorithm #2 (sum): 7547 7 license_eoe
MD5 checksum: 05A65EE03BEE71A464D4B7AB9962F228

Filename: license_eoe.books
Algorithm #1 (sum -r): 03494 907 license_eoe.books
Algorithm #2 (sum): 25664 907 license_eoe.books
MD5 checksum: AE86ED7D3C36F67C2505C06C41FCD174

Filename: license_eoe.idb
Algorithm #1 (sum -r): 15441 58 license_eoe.idb
Algorithm #2 (sum): 59702 58 license_eoe.idb
MD5 checksum: 811CD48FA5BD57E79B4D36839185EED9

Filename: license_eoe.man
Algorithm #1 (sum -r): 63961 271 license_eoe.man
Algorithm #2 (sum): 25496 271 license_eoe.man
MD5 checksum: 3086F992150A673C5110CCC16E20CA96

Filename: license_eoe.sw
Algorithm #1 (sum -r): 05953 7483 license_eoe.sw
Algorithm #2 (sum): 33599 7483 license_eoe.sw
MD5 checksum: BE52C7C2CCDAB2B491F6FA0412E4A66D

**** IRIX 6.3 ****
The license manager softwares provided with this version of
IRIX are not vulnerable to these security issues.

Sun Microsystems, Inc.

CERT/CC Contact Information

Email: cert@cert.org
Phone: +1 412-268-7090 (24-hour hotline)
Fax: +1 412-268-6989
Postal address:

CERT Coordination Center
Software Engineering Institute
Carnegie Mellon University
Pittsburgh PA 15213-3890
U.S.A.

CERT/CC personnel answer the hotline 08:00-17:00 EST(GMT-5) / EDT(GMT-4) Monday through Friday; they are on call for emergencies during other hours, on U.S. holidays, and on weekends.

Using encryption

We strongly urge you to encrypt sensitive information sent by email. Our public PGP key is available from

http://www.cert.org/CERT_PGP.key

If you prefer to use DES, please call the CERT hotline for more information.

Getting security information

CERT publications and other security information are available from our web site

http://www.cert.org/

* "CERT" and "CERT Coordination Center" are registered in the U.S. Patent and Trademark Office.

NO WARRANTY
Any material furnished by Carnegie Mellon University and the Software Engineering Institute is furnished on an "as is" basis. Carnegie Mellon University makes no warranties of any kind, either expressed or implied as to any matter including, but not limited to, warranty of fitness for a particular purpose or merchantability, exclusivity or results obtained from use of the material. Carnegie Mellon University does not make any warranty of any kind with respect to freedom from patent, trademark, or copyright infringement.

Copyright 1997 Carnegie Mellon University.

Sep. 26, 1997 Updated copyright statement

Jan. 22, 1997 Updates - Added SGI and Sun patch information.