Date: 24 Mar 1994 15:46:09 -0500 From: Pete Hammes Subject: ASSIST 94-10 To: assist-bulletin@assist.ims.disa.MIL Content-transfer-encoding: 7BIT -----BEGIN PRIVACY-ENHANCED MESSAGE----- Proc-Type: 4,MIC-CLEAR Content-Domain: RFC822 Originator-Certificate: MIICozCCAgwCAREwDQYJKoZIhvcNAQECBQAwgYYxC zAJBgNVBAYTAlVTMSswKQYDVQQKEyJEZWZlbnNlIEluZm9ybWF0aW9uIFN5c3Rlb XMgQWdlbmN5MTAwLgYDVQQLEydDZW50ZXIgZm9yIEluZm9ybWF0aW9uIFN5c3Rlb XMgU2VjdXJpdHkxGDAWBgNVBAsTD0NvdW50ZXJtZWFzdXJlczAeFw05MzEyMDkxO DU5MTZaFw05NTEyMDkxODU5MTZaMIGxMQswCQYDVQQGEwJVUzErMCkGA1UEChMiR GVmZW5zZSBJbmZvcm1hdGlvbiBTeXN0ZW1zIEFnZW5jeTEwMC4GA1UECxMnQ2Vud GVyIGZvciBJbmZvcm1hdGlvbiBTeXN0ZW1zIFNlY3VyaXR5MRgwFgYDVQQLEw9Db 3VudGVybWVhc3VyZXMxEzARBgNVBAsTCk9wZXJhdGlvbnMxFDASBgNVBAMTC1Bld GUgSGFtbWVzMIGaMAoGBFUIAQECAgQAA4GLADCBhwKBgQDFFJkcaDOuS+6Ai2vmT bwY6JRbhdzPsl6X60hnXruOw2WvrAhc8BTFB+id75m3M55i+Th6MxWH20QHyQq5u yVghOu/s37OxIrj7irNPjtUdPv8b2m4hNGEW53QH6GmXkxLmgLzOhookpoYPC+uw 2MzibDnleVI50d2m//XsWs7hwIBAzANBgkqhkiG9w0BAQIFAAOBgQDHH6CmBoyWU zPlqVnEWYKIBsifqdTJzkKfnoST7NDRIakUP49FP86Cyy1+2AKpUCWaxjq+wGHCH RCNFCCrOwdC9z8XwJal/c69ml6eLRhOoX77ANndpU9E5+eHxP+6Ute6lc63K7+Lz 5xOULjmgaMmKDkTXveVcQO6R2CTY37vcA== Issuer-Certificate: MIICNTCCAZ4CASIwDQYJKoZIhvcNAQECBQAwRDELMAkGA 1UEBhMCVVMxCzAJBgNVBAgTAk1EMSgwJgYDVQQKEx9UcnVzdGVkIEluZm9ybWF0a W9uIFN5c3RlbXMgUENBMB4XDTk0MDIyNTE0NDkxMloXDTk0MDMwNzE0NDkxMlowg YYxCzAJBgNVBAYTAlVTMSswKQYDVQQKEyJEZWZlbnNlIEluZm9ybWF0aW9uIFN5c 3RlbXMgQWdlbmN5MTAwLgYDVQQLEydDZW50ZXIgZm9yIEluZm9ybWF0aW9uIFN5c 3RlbXMgU2VjdXJpdHkxGDAWBgNVBAsTD0NvdW50ZXJtZWFzdXJlczCBmjAKBgRVC AEBAgIEAAOBiwAwgYcCgYEA19l6BN7iTGYEU61qJETIjBh3iAeHzoL8sZ5KwFRZD S/a1KnYlD1zJHR/KeQCOBWW2HzX43TFLCNGU7UD9i6m8AymLe5IJf/bGh0Rne7Jd Q1GAOLw7/J4hE57IMbGETZpzeU1D9IYxiERRNio/oa422lUlS9JZHLA5jaPNcUrX P8CAQMwDQYJKoZIhvcNAQECBQADgYEApkliqAdudoOxvOFmQkOZbSgtlpn61VcNC R7azDNJa2ulevaebptwSTs2OvMeuR/J0Ez4TC7XrJXLVjI5huRAqc+EWGRpZYRMa CARZyE7gGYjUqS7DIQazfskeWiB8zheyW5tCVn+jnB09AZXtgbM6qRjyqrmSdCpg CtfgazIKqI= Issuer-Certificate: MIIB8jCCAVsCAQEwDQYJKoZIhvcNAQECBQAwRDELMAkGA 1UEBhMCVVMxCzAJBgNVBAgTAk1EMSgwJgYDVQQKEx9UcnVzdGVkIEluZm9ybWF0a W9uIFN5c3RlbXMgUENBMB4XDTkzMDUyODE3MTEyN1oXDTk1MDUyODE3MTEyN1owR DELMAkGA1UEBhMCVVMxCzAJBgNVBAgTAk1EMSgwJgYDVQQKEx9UcnVzdGVkIEluZ m9ybWF0aW9uIFN5c3RlbXMgUENBMIGaMAoGBFUIAQECAgQAA4GLADCBhwKBgQDbL xaRlS3u54yyRgVDI5dcE9nlasL8fJqOGlyo7xH2FZnr3kUfsFj7OGiYsr6UbvqwK nyfMIRUrXDUa64leGmft3SK27psDUHOynRSCc40d/HrDf810U5tnTamBKUIMqivK 4GoL0tMRA1eX6hALAvLLgK1HbnwZAo6GqQGW8CIJQIBAzANBgkqhkiG9w0BAQIFA AOBgQDBp5aC6oV6IuFi8JCctq57bew604HHNllgjjp7zdXafq6jctRg2g91k/yFW h19bJC/tNrb0WVwuZOs5L/FToPMNIIHzaW/YSROBmyhTDYaKHZGj0P1+iNjMbHt9 dm1QEHGIfKgBwFidItnOa74DfkXdijlPRnr/+E2Ib6PM+hEfQ== MIC-Info: RSA-MD5,RSA,gqWxhuiol4kuu+6SFmB0PFqzGg0Qb4yOLwbmOF0Nj2c 4vchTEcWygC7E0ZOiPmD+8Eoh3kF3xs3Zz6+0LyV21mACURq0dQ5Hxf6tQwP9cBH S9mgX7UQxv2Dk7Wk+Hi5OGfdWQwBQzjn2R7wS9ntFrNT1PVzrmnT5xbdbrqIWFxU = <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Automated Systems Security Incident Support Team _____ ___ ___ _____ ___ _____ | / /\ / \ / \ | / \ | | / Integritas / \ \___ \___ | \___ | | < et /____\ \ \ | \ | | \ Celeritas / \ \___/ \___/ __|__ \___/ | |_____\ <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Bulletin 94-10 Release date: 24 March 1994, 3:40 PM EST Subject: Writable /etc/utmp Vulnerability SUMMARY: This bulletin contains information about a vulnerability that exists on systems that have an /etc/utmp file that is writable by any user on the system. This vulnerability has been exploited in recent network incidents (see ASSIST 94-02), and ASSIST strongly recommends that sites take immediate action to eliminate this problem from all affected systems. The problem is known to affect Sun Microsystems Inc. SunOS 4.1.X and Solaris 1.1.1 operating systems. Solbourne Computer Inc. and other Sparc products using SunOS 4.1.X or Solaris 1.1.1 are also affected. Solaris 2.x is not affected by this problem. Patches can be obtained from Sun Answer Centers worldwide, and via anonymous FTP from ftp.uu.net in the /systems/sun/sun-dist directory and in Europe from ftp.eu.net in the /sun/fixes directory. The following vendors reported that their operating systems, as distributed by the vendor, are not affected by this problem: Convex Computer Corporation Digital Equipment Corporation Data General Corporation Hewlett-Packard Company IBM Intergraph Motorola, Inc. NeXT, Inc. Pyramid Technology Corporation Sequent Computer Systems Sony Corporation ASSIST recommends that sites check write privileges on /etc/utmp files. If your site uses an operating system that is not listed above and you determine that /etc/utmp is writable by anyone other than root, contact your vendor or ASSIST and report the problem. If writing to the /etc/utmp is restricted to root only, the system is not affected by this vulnerability. BACKGROUND: If the file /etc/utmp is writable by users other than root, programs that trust the information stored in that file can be subverted. IMPACT: This vulnerability allows anyone with access to a user account to gain root access. RECOMMENDED SOLUTION: The solutions to this vulnerability are to either (A) protect the file, or (B) patch all the programs that trust the file. A. To protect the file, make /etc/utmp writable by root only: # chown root /etc/utmp # chmod 644 /etc/utmp B. Patches from Sun Microsystems: Program Patch ID Patch File Name ------- --------- --------------- in.comsat 100272-07 100272-07.tar.Z dump 100593-03 100593-03.tar.Z syslogd 100909-02 100909-02.tar.Z in.talkd 101480-01 101480-01.tar.Z shutdown 101481-01 101481-01.tar.Z write 101482-01 101482-01.tar.Z Program BSD SVR4 MD5 Digital Signature Checksum Checksum ------- --------- --------- -------------------------------- in.comsat 26553 39 64651 78 912ff4a0cc8d16a10eecbd7be102d45c dump 52095 242 41650 484 cdba530226e8735fae2bd9bcbfa47dd0 syslogd 61539 108 38239 216 b5f70772384a3e58678c9c1f52d81190 in.talkd 47917 44 32598 88 5c3dfd6f90f739100cfa4aa4c97f01df shutdown 46562 80 56079 159 bfc257ec795d05646ffa733d1c03855b write 61148 41 48636 81 f93276529aa9fc25b35679ebf00b2d6f ASSIST would like to thank the CERT Coordination Center for information contained in this bulletin. ASSIST is an element of the Defense Information Systems Agency (DISA), Center for Information Systems Security (CISS), that provides service to the entire DoD community. If you are a constituent of the DoD and have any questions about ASSIST or computer security issues, contact ASSIST using one of the methods listed below. If your organization/institution is non-DoD, contact your Forum of Incident Response and Security Teams (FIRST) representative. You can obtain a list of FIRST member organizations and their constituencies by sending email to docserver@first.org with an empty "subject" line and a message body containing the line "send first-contacts". ASSIST INFORMATION RESOURCES: If you would like to be included in the distribution list for these bulletins, send your Milnet (Internet) e-mail address to assist-request@assist.ims.disa.mil. Back issues of ASSIST bulletins, and other security related information, are available from the ASSIST BBS at 703-756-7993/ 1154 DSN 289, and through anonymous FTP from assist.ims.disa.mil (IP address 137.130.234.30). Note: assist.ims.disa.mil will only accept anonymous FTP connections from Milnet addresses that are registered with the NIC or DNS. ASSIST contact information: PHONE: 703-756-7974, DSN 289, duty hours are 06:00 to 22:30 EST Monday through Friday. During off duty hours, weekends, and holidays, ASSIST can be reached via pager at 800-SKY-PAGE (800-759-7243) PIN 2133937. Your page will be answered within 30 minutes, however if a quicker response is required, prefix your phone number with "999". ELECTRONIC MAIL: Send to assist@assist.ims.disa.mil. ASSIST BBS: Leave a message for the "sysop". Privacy Enhanced Mail (PEM): ASSIST uses PEM, a public key encryption tool, to digitally sign all bulletins that are distributed through e-mail. The section of seemingly random characters between the "BEGIN PRIVACY-ENHANCED MESSAGE" and "BEGIN ASSIST BULLETIN" contains machine-readable digital signature information generated by PEM, not corrupted data. PEM software for UNIX systems is available from Trusted Information Systems (TIS) at no cost, and can be obtained via anonymous FTP from ftp.tis.com (IP 192.94.214.96). Note: The TIS software is just one of several implementations of PEM currently available and additional versions are likely to be offered from other sources in the near future. -----END PRIVACY-ENHANCED MESSAGE-----