Infection Channel: Dropped by other malware
This malware arrives as an executable file infected by a file infector malware detected as PE_SALITY.AC. This consequently executes both payloads of BKDR_RILER.SVR and PE_SALITY.AC on the affected system.
To get a one-glance comprehensive view of the behavior of this Backdoor, refer to the Threat Diagram shown below.

This backdoor may be dropped by other malware.
It connects to a website to send and receive information.
File size: 17,920 bytes
File type: PE
Memory resident: Yes
Initial samples received date: 06 Apr 2012
Payload: Connects to URLs/IPs, Compromises system security
Arrival Details
This backdoor may be dropped by the following malware:
Installation
This backdoor drops the following files:
- %System%\goopnet.ini - contains the path and filename of the executed malware
- %System%\utntweep.dll - also detected as BKDR_RILER.SVR
(Note: %System% is the Windows system folder, which is usually C:\Windows\System on Windows 98 and ME, C:\WINNT\System32 on Windows NT and 2000, or C:\Windows\System32 on Windows XP and Server 2003.)
Backdoor Routine
This backdoor connects to the following websites to send and receive information:
- losang.{BLOCKED}dns.co.uk
NOTES:
As an autostart technique, it registers its DLL component as Layered Service Provider (LSP) by creating the following registry entry:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\WinSock2\Parameters\Protocol_Catalog9\Catalog_Entries\0000000000{2 digit numbers}
PackedCatalogItem = "%System%\utntweep.dll"
The DLL component contains the backdoor routines of this malware. The DLL component first checks if it is injected in any of the following processes before continuing execution:
- explorer.exe
- firefox.exe
- lsvchost.exe
- msimn.exe
- msnmsgr.exe
- netscp.exe
- opera.exe
- outlook.exe
- safari.exe
- yahoomessenger.exe
Otherwise, it terminates.
It is capable of reporting the following information to its C&C server:
- Host name
- IP address
- Malware file size
- Malware version
- Operating system
It may then open a hidden instance of COMMAND.COM or CMD.EXE process in order to allow remote command shell access to the attacker.
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