-----BEGIN PGP SIGNED MESSAGE----- ============================================================================= AL-96.03 AUSCERT Alert Vulnerability in Solaris 2.x admintool 30 July 1996 - ----------------------------------------------------------------------------- AUSCERT has received a report of a vulnerability in the Sun Microsystems Solaris 2.x distribution involving the program admintool. This program is used to provide a graphical user interface to numerous system administration tasks. This vulnerability may allow a local user to gain root privileges. Exploit details involving this vulnerability have been made publicly available. At this stage, AUSCERT is not aware of any official patches. AUSCERT recommends that sites take the actions suggested in Section 3 until official patches are available. - ----------------------------------------------------------------------------- 1. Description admintool is a graphical user interface that enables an administrator to perform several system administration tasks on a system. These tasks include the ability to manage users, groups, hosts and other services. To help prevent different users updating system files simultaneously, admintool uses temporary files as a locking mechanism. The handling of these temporary files is not performed in a secure manner, and hence it may be possible to manipulate admintool into creating or writing to arbitrary files on the system. These files are accessed with the effective uid of the process executing admintool. In Solaris 2.5, admintool is set-user-id root by default. That is, all file accesses are performed with the effective uid of root. An effect of this is that the vulnerability will allow access to any file on the system. If the vulnerability is exploited to try and create a file that already exists, the contents of that file will be deleted. If the file does not exist, it will be created with root ownership and be world writable. In earlier versions of Solaris 2.x, admintool is not set-user-id root by default. In this case, admintool runs only with the privileges of the user executing it. However, local users may wait for a specific user to execute admintool, exploiting the vulnerability to create or write files with that specific users' privileges. Again, files created in this manner will be world writable. 2. Impact A local user may be able to create or write to arbitrary files on the system. This can be leveraged to gain root privileges. 3. Workarounds/Solution Currently, AUSCERT is not aware of any official patches which address this vulnerability. When official patches are made available, AUSCERT suggests that they be installed. Until official patches are available sites are encouraged to completely prevent execution of admintool by any user (including root). # chmod 400 /usr/bin/admintool # ls -l /usr/bin/admintool -r-------- 1 root sys 303516 Oct 27 1995 /usr/bin/admintool Note that if only the setuid permissions are removed, it is still possible for users to gain privileges when admintool is executed as root. AUSCERT recommends that, where possible, admintool should not be used at all until official patches are available. In the interim, system administrators should perform administration tasks by using the command line equivalents. More details on performing these tasks may be found in the Sun documentation set. - ----------------------------------------------------------------------------- AUSCERT wishes to thank Brian Meilak (QUT), Marek Krawus (UQ), Leif Hedstrom, Kim Holburn and Michael James for their assistance in this matter. - ----------------------------------------------------------------------------- The AUSCERT team have made every effort to ensure that the information contained in this document is accurate. However, the decision to use the information described is the responsibility of each user or organisation. The appropriateness of this document for an organisation or individual system should be considered before application in conjunction with local policies and procedures. AUSCERT takes no responsibility for the consequences of applying the contents of this document. If you believe that your system has been compromised, contact AUSCERT or your representative in FIRST (Forum of Incident Response and Security Teams). AUSCERT is located at The University of Queensland within the Prentice Centre. AUSCERT is a full member of the Forum of Incident Response and Security Teams (FIRST). AUSCERT maintains an anonymous FTP service which is found on: ftp://ftp.auscert.org.au/pub/. This archive contains past SERT and AUSCERT Advisories, and other computer security information. AUSCERT also maintains a World Wide Web service which is found on: http://www.auscert.org.au/. Internet Email: auscert@auscert.org.au Facsimile: (07) 3365 4477 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. Postal: Australian Computer Emergency Response Team c/- Prentice Centre The University of Queensland Brisbane Qld. 4072. 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