Trojan:Win32/Sirefef.C is the detection for a component of the Win32/Sirefef family.
Trojan:Win32/Sirefef.C is injected into any process that loads the system file "mswsock.dll"; see also the description for Trojan:WinNT/Sirefef.C elsewhere in the encyclopedia.
Downloads arbitrary files
Trojan:Win32/Sirefef.C downloads a configuration file from a remote server. At the time of writing, details about this file were not available.
The trojan also attempts to redirect traffic to malicious websites, such as "intensedive.com".
Analysis by Chun Feng
There are no common symptoms associated with this threat. Alert notifications from installed antivirus software may be the only symptoms.