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TrojanDownloader:Win32/Chekafe.A


TrojanDownloader:Win32/Chekafe.A is a trojan that downloads and executes arbitrary files from a remote host. It also checks if the affected system is in an Internet Café; if so, it sends this information and the system's MAC address, to a remote host.


What to do now

Manual removal is not recommended for this threat. To detect and remove this threat and other malicious software that may have been installed, run a full-system scan with an up-to-date antivirus product such as Microsoft Security Essentials, or the Microsoft Safety Scanner. For more information about using antivirus software, see http://www.microsoft.com/security/antivirus/av.aspx.

Threat behavior

TrojanDownloader:Win32/Chekafe.A is a trojan that downloads and executes arbitrary files from a remote host. It also checks if the affected system is in an Internet Café; if so, it sends this information and the system's MAC address, to a remote host.
Installation
Upon execution, TrojanDownloader:Win32/Chekafe.A modifies the system registry as a mark of its successful installation:
 
Adds value: "ListVer"
With data: "1.0"
To subkey: HKLM\Software\CPACO
Payload
Downloads and executes arbitrary files
TrojanDownloader:Win32/Chekafe.A connects to remote hosts to download and execute arbitrary files in the affected system. In the wild, TrojanDownloader:Win32/Chekafe.A has been observed to contact the following host for this purpose:
  • viper.eloer.cn
 
At the time of writing, the downloaded files are online game password stealer trojans, including the following:
 
Sends information to a remote server
TrojanDownloader:Win32/Chekafe.A checks whether the following processes are running on the affected system:
 
BarClientView.exe
Barclient.exe
EWay.exe
NBClient.exe
NxpAuxSvc.exe
clsmn.exe
mzdclient.exe
 
These processes are related to software used in Internet Café administration. By searching these processes, Win32/Chekafe attempts to determinate whether the affected system is in an Internet Cafe or not. If so, it then posts this information, as well as the MAC address of the system, to a remote host.
 
Stop system service
TrojanDownloader:Win32/Chekafe.A attempts to stop the "sharedaccess" service to disable Windows Firewall/Internet Connection Sharing.
 
Analysis by Chun Feng

Symptoms

System changes
The following system changes may indicate the presence of this malware:
  • The presence of the following registry entry:
    Added value: "ListVer"
    With data: "1.0"
    To subkey: HKLM\Software\CPACO

Prevention


Alert level: Severe
First detected by definition: 1.71.1143.0
Latest detected by definition: 1.173.2181.0 and higher
First detected on: Dec 21, 2009
This entry was first published on: Jan 06, 2010
This entry was updated on: Apr 17, 2011

This threat is also detected as:
  • Trojan-Downloader.Win32.Agent.cxzk (Kaspersky)
  • Trojan.DL.Chekafe.Gen (VirusBuster)
  • Trojan.DownLoad1.21027 (Dr.Web)
  • Win32/TrojanDownloader.Chekafe.A (ESET)