The malware is detected as Trojan-Dropper:W32/Bohu.A and is a NullSoft installer that contains the following:
Besides installing the files, it also modify the system's IP settings to use DHCP.
This file is an installer of a media player application. This is a decoy installed by the malware to make users think they have installed a valid application.
This file is some sort of utility that is being used by the malware for its different routines.
This utility is able to do the following:
- append garbage data to the end of a file
- modify DNS settings
- compress and uncompress samples
This utility is detected as Trojan.Generic.4982818.
This file is the compressed form of another Nullsoft installer which contains the malicious components of the malware. The installer (setup321046.exe) is extracted by the malware using the msfsg.exe utility.
SETUP321046.EXE contains the following:
After extracting the files, SETUP321046.EXE will use msfsg.exe to append garbage data to the following files:
Then it copies the following files:
- newnetgar.dll -> %System%\nethome32.dll
- spass.dll -> %System%\netplayone\netplayone.dll
SETUP321046.EXE will create the following registry entries/service:
- HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\WinSock2\speednet_sph PathName = %System%\netplayone\netplayone.dll
SETUP321046.EXE will then launch DSETUP.EXE to install the following NDIS driver and notify object:
- siglow.sys -> %System%\drivers\siglow.sys
- siglow.dll -> %System%\drivers\siglow.dll
SETUP321046.EXE also attempts to change the DNS settings to 126.96.36.199 and 188.8.131.52 using the msfsg.exe utility.
NEWNETGAR.DLL / NETHOME32.DLL
This component contains routines that connects to http://[...].gogle.cn/ to obtain updates and other settings. It is detected as Backdoor:W32/Bohu.A.
SPASS.DLL / NETPLAYONE.DLL
This component monitors network traffic related to the following AV-related processes:
It modifies traffic made by these processes to the following addresses:
These addresses are related to AV cloud services. By doing this, the malware may disable cloud-based protection of the affected product.
This component also modifies traffic to several addresses related to the following domains:
It connects to the following for the settings:
This component is detected as Trojan:W32/Bohu.A.
SIGLOW.SYS / SIGLOW.DLL
These components are responsible for dropping network traffic to the following AV related sites:
These components are also detected as Trojan:W32/Bohu.A.