Security giant Symantec has spotted a spam campaign designed to get malware on anti-Putin campaigner PCs.
Vladimir Putin was re-elected as president of Russia last week, but there have been protests against his rule both pre and post-election.
Now, spam messages have been sent out purporting to contain instructions for rallies against Putin.
The emails included an attachment detected by Symantec as Trojan.Dropper, but those who see the document are presented with details of an apparent anti-Putin meeting that even features a map.
From a spam perspective, this attack is quite unusual mainly because of its size.
However, malicious macros, if enabled, will be running in the background and "a particularly nasty Trojan" is activated, the security giant found.
Various files are then deleted from the user's machine, including .doc, .exe, .xls and .zip files.
"The Trojan also attempts to connect to IP address 193.104.153.31 (down at the time of analysis), which contains links to the notorious Trojan.Smoaler threat," said Symantec's Stephen Doherty, in a blog post.
"Smoaler recently used the surero48421.ru domain as part of its command-and-control server and this website formerly resolved to the above IP address.
"Once it has destroyed all of the above files by overwriting them, it then runs code to cause the computer to crash (blue screen) through a call to the RtlSetProcessIsCritical API."
Symantec also noted how unusual the spam attack was, pointing to the size of the emails.
"From a spam perspective, this attack is quite unusual mainly because of its size (average of more than 500 KB). Most spam messages do not exceed 10 KB," Doherty added.
"For example, in the latest Symantec Intelligence report, 56 per cent of all February spam messages were less than 5 KB with 30 per cent between 5 - 10 KB and only 13 per cent greater than 10 KB."
