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- CA-92:16 CERT Advisory
- September 22, 1992
- VMS Monitor Vulnerability
-
- ---------------------------------------------------------------------------
-
- The CERT Coordination Center has received information concerning a
- potential vulnerability with Digital Equipment Corporation's VMS
- Monitor. This vulnerability is present in V5.0 through V5.4-2 but has
- been corrected in V5.4-3 through V5.5-1. The Software Security
- Response Team at Digital has provided the following information
- concerning this vulnerability.
-
- NOTE: Digital suggests that customers who are unable to upgrade their
- systems implement the workaround described below.
-
- For additional information, please contact your local Digital Equipment
- Corporation customer service representative.
-
-
- Beginning of Text provided by Digital Equipment Corporation
- ==============================================================================
- SSRT-0200 PROBLEM: Potential Security Vulnerability Identified in Monitor
- SOURCE: Digital Equipment Corporation
- AUTHOR: Software Security Response Team - U.S.
- Colorado Springs USA
-
- PRODUCT: VMS
- Symptoms Identified On: VMS, Versions 5.0, 5.0-1, 5.0-2, 5.1, 5.1-B,
- 5.1-1, 5.1-2, 5.2, 5.2-1, 5.3,
- 5.3-1, 5.3-2, 5.4, 5.4-1, 5.4-2
-
- *******************************************************
- SOLUTION: This problem is not present in VMS V5.4-3
- (released in October 1991) through V5.5-1
- (released in July, 1992.)
- *******************************************************
- Copyright (c) Digital Equipment Corporation, 1992 All Rights Reserved.
- Published Rights Reserved Under The Copyright Laws Of The United States.
- -------------------------------------------------------------------------------
- PROBLEM/IMPACT:
- -------------------------------------------------------------------------------
- Unauthorized privileges may be expanded to authorized users of a system
- under certain conditions, via the Monitor utility. Should a system be
- compromised through unauthorized access, there is a risk of potential
- damage to a system environment. This problem will not permit unauthorized
- access entry, as individuals attempting to gain unauthorized access will
- continue to be denied through the standard VMS security mechanisms.
- -------------------------------------------------------------------------------
- SOLUTION:
- -------------------------------------------------------------------------------
- This potential vulnerability does not exist in VMS V5.4-3
- (released in October 1991) and later versions of VMS through V5.5-1.
-
- Digital strongly recommends that you upgrade to a minimum of VMS V5.4-3,
- and further, to the latest release of VMS V5.5-1. (released in July, 1992)
- ------------------------------------------------------------------------------
- INFORMATION:
- -------------------------------------------------------------------------------
- If you cannot upgrade at this time Digital recommends that you
- implement a workaround (examples attached below) to avoid any potential
- vulnerability.
-
- As always, Digital recommends that you periodically review your system
- management and security procedures. Digital will continue to review and
- enhance the security features of its products and work with customers to
- maintain and improve the security and integrity of their systems.
- -------------------------------------------------------------------------------
- WORKAROUND
- -------------------------------------------------------------------------------
- A suggested workaround would be to remove the installed image
- SYS$SHARE:SPISHR.EXE via VMS INSTALL and/or restrict the use of
- the MONITOR utility to "privileged" system administrators.
- Below are the examples of doing both;
-
- [1] To disable the MONITOR utility the image SYS$SHARE:SPISHR.EXE should be
- deinstalled.
-
- From a privileged account;
-
- For cluster configurations;
- ---------------------------
-
- $ MC SYSMAN
- SYSMAN> SET ENVIRONMENT/CLUSTER
- SYSMAN> DO INSTALL REMOVE SYS$SHARE:SPISHR.EXE
- SYSMAN> DO RENAME SYS$SHARE:SPISHR.EXE SPISHR.HOLD
- SYSMAN> EXIT
-
- For non-VAXcluster configurations;
- ---------------------------------
-
- $INSTALL
- INSTALL>REMOVE SYS$SHARE:SPISHR.EXE
- INSTALL>EXIT
- $RENAME SYS$SHARE:SPISHR.EXE SPISHR.HOLD
-
-
- [2] If you wish to restrict access to the MONITOR command so that only a
- limited number of authorized (or privileged) persons are granted access
- to the utility, one method might be to issue the following
- example commands;
-
- From a privileged account;
-
- For cluster configurations;
- ---------------------------
-
- $ MC SYSMAN
- SYSMAN> SET ENVIRONMENT/CLUSTER
- SYSMAN> DO INSTALL REMOVE SYS$SHARE:SPISHR.EXE
- SYSMAN> DO SET FILE/ACL=(ID=*,ACCESS=NONE) SYS$SHARE:SPISHR.EXE
- SYSMAN> DO SET FILE/ACL=(ID=SYSTEM,ACCESS=READ+EXECUTE) SYS$SHARE:SPISHR.EXE
- SYSMAN> DO INSTALL ADD SYS$SHARE:SPISHR.EXE/OPEN/HEADER/SHARE/PROTECT
- SYSMAN> EXIT
- $
- THIS WILL IMPACT the MONITOR UTILITY FOR REMOTE MONITORING.
- LOCAL MONITORING WILL CONTINUE TO WORK FOR PERSONS HOLDING THE ID's
- GRANTED ACL ACCESS.
-
- see additional note(s) below
-
- For non-VAXcluster configurations;
- ----------------------------------
-
- $ INSTALL
- INSTALL>REMOVE SYS$SHARE:SPISHR.EXE
- INSTALL>EXIT
- $ SET FILE /ACL=(ID=*,ACCESS=NONE) SYS$SHARE:SPISHR.EXE
- $ SET FILE /ACL=(ID=SYSTEM,ACCESS=READ+EXECUTE) SYS$SHARE:SPISHR.EXE
- $ INSTALL
- INSTALL>ADD SYS$SHARE:SPISHR.EXE/OPEN/HEADER/SHARE/PROTECT
- INSTALL>EXIT
- $
-
- IN THE ABOVE EXAMPLES, THE "SET FILE /ACL" LINE SHOULD BE REPEATED FOR
- ALL ACCOUNTS THAT ARE REQUIRED/ALLOWED TO USE THE DCL MONITOR COMMAND.
-
- NOTE: The ID -SYSTEM- is an example, and should be
- substituted as necessary with valid user ID's that are
- associated with accounts you wish to grant access to.
-
- ===========================================================================
- End of Text provided by Digital Equipment Corporation
-
-
- ---------------------------------------------------------------------------
- CERT wishes to thank Teun Nijssen of CERT-NL (the SURFnet CERT, in the
- Netherlands) for bringing this security vulnerability to our attention.
- We would also like to thank Digital Equipment Corporation's Software Security
- Response Team for providing information on this vulnerability.
- ---------------------------------------------------------------------------
-
- If you believe that your system has been compromised, contact CERT or
- your representative in FIRST (Forum of Incident Response and Security Teams).
-
- Internet E-mail: cert@cert.org
- Telephone: 412-268-7090 (24-hour hotline)
- CERT personnel answer 7:30 a.m.-6:00 p.m. EST(GMT-5)/EDT(GMT-4),
- on call for emergencies during other hours.
-
- CERT Coordination Center
- Software Engineering Institute
- Carnegie Mellon University
- Pittsburgh, PA 15213-3890
-
- Past advisories, information about FIRST representatives, and other
- information related to computer security are available for anonymous ftp
- from cert.org (192.88.209.5).
-