It has recently come to light there is a security exploit that seems to be affecting or targeting Cloud Linux and CentOS systems running cPanel. We believe the exploit is done via SSH server.
SSHD rootKit exploit libkeyutils.so
So far cloudlinux know:
Rootkit deposits files /lib64/libkeyutils.so.1.9 on 64bit systems and /lib/libkeyutils.so.1.9 on 32bit systems
It changes link: /lib64/libkeyutils.so.1 (and /lib/libkeyutils.so.1) to point to that library.
We believe this library is:
Hacker has full root access, and can do absolutely anything with the server. stealing passwords, ssh keys & /etc/shadow from the system used as a backdoor to access server at any time send spam.
Run the following shell script to find if your server infected.
#vi check.sh
#!/bin/bash LIB64=/lib64/libkeyutils.so.1.9 LIB64_1=/lib64/libkeyutils-1.2.so.2 LIB32=/lib/libkeyutils.so.1.9 LIB32_1=/lib/libkeyutils-1.2.so.2 if [ -f $LIB64 ]; then echo The server is compromised, $LIB64 found exit 0 fi if [ -f $LIB64_1 ]; then echo The server is compromised, $LIB64_1 found exit 0 fi if [ -f $LIB32 ]; then echo The server is compromised, $LIB32 found exit 0 fi if [ -f $LIB32_1 ]; then echo The server is compromised, $LIB32_1 found exit 0 fi echo "Cannot find compromised library" exit 1
#chmod 755 check.sh
#sh check.sh
Use the following script to To clean up libkeyutils library.
USE IT AT YOUR OWN RISK, THE SCRIPT WASN’T FULLY TESTED
#vi clean
#!/bin/bash LIB64_13=/lib64/libkeyutils.so.1.3 LIB64_12=/lib64/libkeyutils-1.2.so LIB64_1=/lib64/libkeyutils.so.1 LIB32_13=/lib/libkeyutils.so.1.3 LIB32_12=/lib/libkeyutils-1.2.so LIB32_1=/lib/libkeyutils.so.1 LIB32="" LIB64="" LIB64_h1=/lib64/libkeyutils.so.1.9 LIB32_h1=/lib/libkeyutils.so.1.9 LIB64_h2=/lib64/libkeyutils-1.2.so.2 LIB32_h2=/lib/libkeyutils-1.2.so.2 LINK="" BAD_LIB="" if [ -f $LIB64_h1 ]; then BAD_LIB=$LIB64_h1 LIB64="HACK" fi if [ -f $LIB64_h2 ]; then BAD_LIB=$LIB64_h2 LIB64="HACK" fi if [ -f $LIB32_h1 ]; then BAD_LIB=$LIB32_h1 LIB64="" LIB32="HACK" fi if [ -f $LIB32_h2 ]; then BAD_LIB=$LIB32_h2 LIB64="" LIB32="HACK" fi #echo $BAD_LIB, 64, $LIB64, 32, $LIB32 if [ "x$LIB64" == "xHACK" ]; then LINK=$LIB64_1 if [ -f $LIB64_12 ]; then FIX_LIB=$LIB64_12 elif [ -f $LIB64_13 ]; then FIX_LIB=$LIB64_13 else echo "Cannot find good libary, giving up" exit 1 fi fi if [ "x$LIB32" == "xHACK" ]; then LINK=$LIB32_1 if [ -f $LIB32_12 ]; then FIX_LIB=$LIB32_12 elif [ -f $LIB32_13 ]; then FIX_LIB=$LIB32_13 else echo "Cannot find good libary, giving up" exit 1 fi fi if [ ! -z "$FIX_LIB" ]; then # echo $LINK, $FIX_LIB $BAD_LIB rm -f $LINK ln -s $FIX_LIB $LINK rm -f $BAD_LIB echo "Clean up is done, please reboot the server ASAP" else echo "Cannot find compromised library" fi
#chmod 755 clean.sh
#sh clean.sh
Reboot your server.
Install CSF/APF firewall and secure your SSH.
Change all of your root passwords and key pairs from a clean computer.
Keep your server software up-to-date.
Disable root logins and/or firewall off your SSH port.
Upgrade Flash and Java on your computers.
Do malware scans on your computers.
1. SSH to server
2. Run ‘updatedb’
3. Run ‘locate libkeyutils.so.1.9′
Please follow the steps below to clear the expliot.
1. SSH to the server
2. cd /lib64/
3. rm libkeyutils.so.1.9
4. rm libkeyutils.so.1
5. ln -s libkeyutils.so.1.3 libkeyutils.so.1
6. Restart ssh
7. yum update kernel and Reboot to close any active connections
For more information, please check with cloud linux blog
http://www.cloudlinux.com/blog/clnews/sshd-exploit.php