Malware dubbed one of the "most advanced global cyber-espionage operations to date” is using old-school virus techniques, according to new research.
A new family of malware dubbed ‘The Mask’ or ‘Careto’, the Spanish for Mask, was revealed in February by cyber-security company Kaspersky, who said the campaign appeared to be state sponsored and originated from the Spanish-speaking country.
But despite its complex nature, after acquiring samples of the malware, researchers at Context Information Security have uncovered classic techniques at the heart of its code commonly employed by virus writers in the 80s and 90s.
The virus uses a file-appending mechanism to infect the boot process of a system, which Context describes as a trick “straight from the history books”, allowing malicious code to run as soon as the operating system starts loading.
“While hidden in the complexity of the malware, Careto or The Mask use the well know technique of infecting the first executable that loads when Windows boots,” says Kevin O’Reilly, a senior researcher at Context.
“This discovery seems to suggest that old tricks are sometimes the best and also begs the question; is this a nod of respect to the virus writers who wreaked havoc in the 90s or have they come out of retirement to develop a new nation-state cyber-weaponry arsenal?”
The Mask is a wide-ranging malware toolset with a variety of capabilities, including intercepting network traffic from a victim’s PC, keystrokes, Skype conversations, PGP encrypion keys, wireless traffic and file activity.
It also has the capability to harvest a wide range of files from the infected system, including encryption and SSH keys, VPN and remote desktop configurations.
According to Kaspersky it had operated undetected since 2007 targeting government agencies, diplomatic embassies, energy companies, research institutions, private equity firms and activists in 31 countries and had infected more than 380 targets before it stopped operating.
“Now that it has been discovered, anti-virus vendors have added detection to their products so it is no longer a real risk,” says O’Reilly.
“The historical attack vector was targeted phishing emails or spear phishing with infected attachments, but is unlikely that this is still happening using this specific toolset. What is unclear is whether this is a one off or a trend to watch out for.”
Full details of the research are available on Context’s blog.