Published:
21 October 1999
Protect yourself against future threats.
-----BEGIN PGP SIGNED MESSAGE----- =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-1999.160 -- RHSA-1999:042-01 screen defaults to not using Unix98 ptys 22 October 1999 =========================================================================== Red Hat, Inc. has released the following advisory concerning a vulnerability in the default permissions on ptys used by 'screen' shipped with Red Hat Linux 6.1. 'screen' leaves the ptys it uses with world read/write permissions. This may allow users to gain privileged access. - --------------------------BEGIN INCLUDED TEXT-------------------- - --------------------------------------------------------------------- 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: Keywords: 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 problem. 3. Bug IDs fixed (http://developer.redhat.com/bugzilla for more info): 6100 4. Relevant releases/architectures: Red Hat Linux 6.1, Intel 5. Obsoleted by: 6. Conflicts with: 7. RPMs required: Red Hat Linux 6.1: Intel: ftp://ftp.redhat.com/pub/redhat/updates/6.1/i386/screen-3.9.4-3.i386.rpm Source package: ftp://ftp.redhat.com/pub/redhat/updates/6.1/SRPMS/screen-3.9.4-3.src.rpm 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: http://www.redhat.com/corp/contact.html 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: - -- - --------------------------END INCLUDED TEXT-------------------- This security bulletin is provided as a service to AusCERT's members. As AusCERT did not write the document quoted above, AusCERT has had no control over its content. The decision to use any or all of this information is the responsibility of each user or organisation, and should be done so in accordance with site policies and procedures. NOTE: This is only the original release of the security bulletin. It may not be updated when updates to the original are made. If downloading at a later date, it is recommended that the bulletin is retrieved directly from the original authors to ensure that the information is still current. Contact information for the authors of the original document is included in the Security Bulletin above. If you have any questions or need further information, please contact them directly. Previous advisories and external security bulletins can be retrieved from: http://www.auscert.org.au/Information/advisories.html If you believe that your system has been compromised, contact AusCERT or your representative in FIRST (Forum of Incident Response and Security Teams). Internet Email: auscert@auscert.org.au Facsimile: (07) 3365 7031 Telephone: (07) 3365 4417 (International: +61 7 3365 4417) AusCERT personnel answer during Queensland business hours which are GMT+10:00 (AEST). On call after hours for emergencies. -----BEGIN PGP SIGNATURE----- Version: 2.6.3i Charset: noconv Comment: ftp://ftp.auscert.org.au/pub/auscert/AUSCERT_PGP.key iQCVAwUBOEJrOyh9+71yA2DNAQGGmwP/Vu/OpBKis2wrNRDfEprp+lU3Yrgul5rN t4w73+MXFo8P+boVRIHhpI5bo/2dyIFTAnaa4hIyrg4cneD4deerv/tEwzecypFg 7ZhVO8WADtXAgyF6f2GwzzZOWtzocNJdRTGgaQ3O74j3AFJSjRc7rzSY1C3rAhqN hSg6z4rM4Uk= =wZPc -----END PGP SIGNATURE-----