F-Secure
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Trojan:W32/DNSChanger
| Name : | Trojan:W32/DNSChanger |
| Category: | Malware |
| Type: | Trojan |
| Platform: | W32 |
Summary
A trojan, or trojan horse, is a seemingly legitimate program which secretly performs other, usually malicious, functions. It is usually user-initiated and does not replicate.
Details
Registry Modifications
Creates these keys:
• HKLM\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\Interfaces\{random}
DhcpNameServer = 85.255.xx.xxx,85.255.xxx.xxx
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
NameServer = 85.255.xxx.133,85.255.xxx.xxx
• HKLM\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\
DhcpNameServer = 85.255.xxx.xxx,85.255.xxx.xxx
DhcpNameServer = 85.255.xxx.xxx,85.255.xxx.xxx
• HKLM\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\
NameServer = 85.255.xxx.xxx,85.255.xxx.xxx
NameServer = 85.255.xxx.xxx,85.255.xxx.xxx
Additional Details
DNSChanger is a trojan that will change the infected system's Domain Name Server (DNS) settings, in order to divert traffic to unsolicited, and potentially illegal sites.
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:
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
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"
"NameServer"