Wiper malware — so called because it erases data from victims’ computer drives — played a key part in the costly cybersecurity breach directed against Sony Pictures Entertainment in late 2014. It is also a demonstration of the murky netherworld in which the distinctions among cyberwar, cyberterrorism and cybercrime can be difficult to draw.

The use of this type of malware so far has been largely associated with politically motivated hacktivists, while some of the victims have been potential targets of intelligence activity directed at or supported by nation-state intelligence organizations.

Patterns of Attack

As David McMillen reports in an IBM MSS research paper, “Wiper Malware Analysis,” such malware has been associated with attacks going back to 2008. At that time, a malware called Narilam was deployed specifically against financial and business software packages that are primarily used in Iran.

In 2009 and 2010, another pair of packages including Wiper malware, Dozer and Koredos were deployed against victims in South Korea. In 2012, a Wiper package called Shamoon was used to cripple 30,000 computers at Saudi Aramco, while a different package, called GrooveMonitor/Maya, was reported in Iran. In 2013, a package called Dark Seoul was deployed against victims in South Korea.

The most recent attack against Sony, which has been associated with North Korea, employed a Wiper software dubbed Destover.

Holding Data Hostage

The sophistication of the attack and the scope of the damage done vary widely among these Wiper malware variants. Some launch a one-time attack on a specific date and erase hard drives, while others gradually corrupt disks over a long period, during which interval they communicate with a remote command-and-control center.

It has been challenging to analyze the Wiper malware because the data erasure commanded by the malware includes eliminating the object image of the malware itself.

Because Wiper destroys data instead of stealing it, its use so far has been primarily associated with politically motivated attacks, whether launched by freelancing ideological hacktivists or by state intelligence operatives. However, attackers can also use the threat of data erasure or exposure as a means of extortion. The scope of the Wiper malware threat may thus extend from intelligence-related activity to cybercrime motivated by a hope of financial gain.

Defending Against Wiper Malware Attacks

Wiper malware can be extremely destructive, as its role in the Sony attack has already demonstrated. As such, purely defensive tactics are insufficient.

Firms and other organizations must take proactive security steps to minimize the risks from the Wiper malware. Crucial intellectual property should be isolated in hardened systems that can be accessed only through privileged connections. Important data should be backed up off-site, and organizations must institute and test an emergency response and recovery plan.

These measures will not provide immunity, but they will make firms better prepared to respond to the threat of Wiper malware.

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