Summary
Trojan:W32/DNSChanger will change the infected system's Domain Name Server (DNS) settings in order to divert traffic to unsolicited, and potentially illegal sites.
Disinfection & Removal
Allow F-Secure Anti-Virus to disinfect the relevant files.
For more general information on disinfection, please see Removal Instructions.
Technical Details
The trojan is usually a small file (about 1.5 kilobytes) that is designed to change the 'NameServer' Registry key value to a custom IP address. This IP address is usually encrypted in the body of a trojan.
As a result of this change, a victim's computer will contact the newly assigned DNS server to resolve names of different webservers.
Variant: Trojan.Win32.DNSChanger.al
Lately we got a few samples of this trojan that were named 'PayPal-2.5.200-MSWin32-x86-2005.exe'. This trojan was programmed to change the DNS server name of a victim's computer to 193.227.227.218 address.
The Registry key that is affected by this trojan is:
- [HKLM\SYSTEM\ControlSet001\Services\Tcpip\Parameters\Interfaces] "NameServer"
Other registry modifications made involve creating these keys:
- HKLM\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\Interfaces\{random} DhcpNameServer = 85.255.xx.xxx,85.255.xxx.xxx
- HKLM\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\Interfaces\{random} NameServer = 85.255.xxx.133,85.255.xxx.xxx
- HKLM\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\ DhcpNameServer = 85.255.xxx.xxx,85.255.xxx.xxx
- HKLM\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\ NameServer = 85.255.xxx.xxx,85.255.xxx.xxx
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