Red Hat Security Advisory: screen defaults to not using Unix98 ptys

Date: Wed, 20 Oct 1999 23:49:28 -0400
From: Bill Nottingham [email protected]
To: [email protected]
Cc: [email protected], [email protected]
Reply to: [email protected]

Red Hat, Inc. Security Advisory

Synopsis: screen defaults to not using Unix98 ptys
Advisory ID: RHSA-1999:042-01
Issue date: 1999-10-20
Updated on:
Cross references: screen unix98 pty permissions

1. Topic:

Screen uses ptys with world read/write permissions.

2. Problem description:

The version of screen that shipped with Red Hat Linux 6.1
defaulted to not using Unix98 ptys. Since screen is not setuid
root, this means that it leaves the ptys with insecure permissions.
The updated packages restore the Unix98 pty support. Thanks go to
Chris Evans for noting this vulnerability.

Previous versions of Red Hat Linux are not affected by this

3. Bug IDs fixed (http://developer.redhat.com/bugzilla
for more info):


4. Relevant releases/architectures:

Red Hat Linux 6.1, Intel

5. Obsoleted by:

6. Conflicts with:

7. RPMs required:

Red Hat Linux 6.1:



Source package:


8. Solution:

For each RPM for your particular architecture, run:

rpm -Uvh ‘filename’

where filename is the name of the RPM.

9. Verification:

MD5 sum                           Package Name
2e5ada61d3d06408bae76bf581d2bf69  screen-3.9.4-3.i386.rpm
09277e5b10b709ac2d974b952cb29e9b  screen-3.9.4-3.src.rpm

These packages are GPG signed by Red Hat, Inc. for security. Our
key is available at:

You can verify each package with the following command:

rpm –checksig ‘filename’

If you only wish to verify that each package has not been
corrupted or tampered with, examine only the md5sum with the
following command:

rpm –checksig –nogpg ‘filename’

10. References: