CERT Vendor Bulletin - HEWLETT-PACKARD SECURITY BULLETIN: #00025
cert-advisory at cert.org
Wed Apr 12 15:59:17 UTC 1995
CERT Vendor-Initiated Bulletin VB-95:03
April 12, 1995
Topic: Sendmail permits unauthorized remote program execution
Source: Hewlett-Packard Company
Related CERT documents: CA-95:05 and CA-94:12, "Sendmail Vulnerabilities"
To aid in the wide distribution of essential security information, the CERT
Coordination Center is forwarding the following information from Hewlett-
Packard. HP urges you to act on this information as soon as possible. HP
contact information is included in the forwarded text below; please contact
them if you have any questions or need further information.
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HEWLETT-PACKARD SECURITY BULLETIN: #00025, 2 April 95
The information in the following Security Bulletin should be acted upon as
soon as possible. Hewlett- Packard will not be liable for any consequences
to any customer resulting from customer's failure to fully implement
instructions in this Security Bulletin as soon as possible.
PROBLEM: Sendmail permits unauthorized remote program execution.
PLATFORM: HP 9000 series 300/400s and 700/800s 8.x and 9.x
DAMAGE: Remote users can cause sendmail to execute any program.
SOLUTION: Apply patch PHNE_5402 (series 700/800, HP-UX 9.x), or
PHNE_5401 (series 700/800, HP-UX 8.x), or
PHNE_5384 (series 300/400, HP-UX 9.x), or
PHNE_5383 (series 300/400, HP-UX 8.x), or
PHNE_5387 (series 700, HP-UX 9.09), or
PHNE_5388 (series 700, HP-UX 9.09+), or
PHNE_5389 (series 800, HP-UX 9.08)
AVAILABILITY: All patches are available now.
I. Vulnerability in /usr/lib/sendmail
A. A vulnerability in sendmail
A vulnerability in sendmail has been discovered that permits
remote users to cause sendmail to execute any program that is
allowed with the permissions:
Files and programs that are not world-writeable or world-executable
and are not in the 'other' group or owned by 'daemon' are
safe from modification. This means that /etc/passwd cannot be
modified, for example.
B. Fixing the problems
The two vulnerabilities can be eliminated from releases 8.x and 9.x of
HP-UX by applying a patch.
Hewlett-Packard recommends that all customers concerned with the
security of their HP-UX systems apply the appropriate patch as
soon as possible.
It is further advised that system administrators closely scan their
mail syslogs for evidence of any unusual activity, using:
grep "|" /usr/spool/mqueue/syslog*
[Editor's note: If your site links grep to egrep or the Gnu grep,
the above command matches every line in the file. An alternative is to
use fgrep where you are looking for the "|" character. -- CERT CC]
If there is any evidence of an intrusion, system administrators are
strongly urged to require password changes for all accounts.
C. How to Install the Patch (for HP-UX 8.x and 9.x)
1. Determine which patch is appropriate for your hardware platform
and operating system:
PHNE_5402 (series 700/800, HP-UX 9.x),
PHNE_5401 (series 700/800, HP-UX 8.x),
PHNE_5384 (series 300/400, HP-UX 9.x),
PHNE_5383 (series 300/400, HP-UX 8.x),
PHNE_5387 (series 700, HP-UX 9.09),
PHNE_5388 (series 700, HP-UX 9.09+),
PHNE_5389 (series 800, HP-UX 9.08)
2. Hewlett Packard's HP-UX patches are available via email
and the World Wide Web.
To obtain a copy of the HP SupportLine email service user's guide,
send the following in the TEXT PORTION OF THE MESSAGE to
support at support.mayfield.hp.com (no Subject is required):
The users guide explains the process for downloading HP-UX patches
via email and other services available.
World Wide Web service for downloading of patches
is available via our URL:
3. Apply the patch to your HP-UX system.
4. Examine /tmp/update.log for any relevant WARNINGs or ERRORs. This
can be done as follows:
a. At the shell prompt, type "tail -60 /tmp/update.log | more"
b. Page through the next three screens via the space bar, looking
for WARNING or ERROR messages.
D. Impact of the patch and workaround
The patch for HP-UX releases 8.x and 9.x provides a new version of
/usr/lib/sendmail which fixes the vulnerability. No patches will be
available for versions of HP-UX prior to 8.0.
E. To subscribe to automatically receive future NEW HP Security
Bulletins from the HP SupportLine mail service via electronic
mail, send an email message to:
support at support.mayfield.hp.com (no Subject is required)
Multiple instructions are allowed in the TEXT PORTION OF THE
MESSAGE, here are some basic instructions you may want to use:
To add your name to the subscription list for new security
bulletins, send the following in the TEXT PORTION OF THE MESSAGE:
To retrieve the index of all HP Security Bulletins issued to date,
send the following in the TEXT PORTION OF THE MESSAGE:
To get a patch matrix of current HP-UX and BLS security
patches referenced by either Security Bulletin or Platform/OS,
put the following in the text portion of your message:
World Wide Web service for browsing of bulletins
is available via our URL:
Choose "Support news", then under Support news,
choose "Security Bulletins"
F. To report new security vulnerabilities, send email to
security-alert at hp.com
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