Data-annihilation attacks don't typically have a long shelf life: They rely on the element of surprise to incur as much damage as possible before they are discovered and purged. But sometimes they have a long tail and continue to spread, like the recently analyzed Narilam malware.

Iran's official Computer Emergency Response Team (CERT) says Narilam is at least 2 years old, and is built to sabotage databases in specific Iranian financial software.

Symantec, which last week revealed that it had found samples of the so-called Narilam self-replicating malware, says the database-destroying malware is still spreading among Middle East computers, and has been around for at least three years. "It's interesting because we don't see too many destructive-type threats around for a very long time" like this one, says Vikram Thakur, principal security response manager at Symantec. "We are still seeing new infections."

A source with knowledge of the malware says despite initial speculation that Narilam was either related or similar to nation-state type attacks like Stuxnet and Flame, Narilam is really just a run-of-the-mill piece of destructive malware code that may have been written by a disgruntled employee of Iranian accounting software firm TarrahSystem, or by one of its competitors attempting to sabotage the vendor.

[Old-school but painful data-destroying malware attacks in the Middle East a red flag to revisit incident response, recovery. See The Data-Annihilation Attack Is Back.]

According to a statement posted by Iran's Maher CERT on its website, Narilam is definitely not a new piece of code, and it is not related to Stuxnet. "The malware called 'narilam' by Symantec was an old malware, previously detected and reported online in 2010 by some other names. This malware has no sign of a major threat, nor a sophisticated piece of computer malware," according to the Iranian CERT. "The sample is not wide spread and is only able to corrupt the database of some of the products by an Iranian software company, those products are accounting software for small businesses. The simple nature of the malware looks more like a try to harm the software company reputation among their customers."

Researchers at Kaspersky Lab this week also shot down the initial suggestion that Narilam was somehow related to Stuxnet and Flame, which have been unofficially attributed to the U.S. and Israel as a way to quash Iran's nuclear weapons efforts. "Narilam is a rather old threat that was probably deployed during late 2009 and mid-2010. Its purpose was to corrupt databases of three financial applications from TarrahSystem, namely Maliran, Amin and Shahd. Several variants appear to have been created, but all of them have the same functionality and method of replication," according to researchers at Kaspersky Lab.

The researchers say 60 percent of the infections occurred in Iran, and 40 percent in Afghanistan. Unlike Symantec's assessment that Narilam is still spreading, Kaspersky says the malware is dying out. "The malware is currently almost extinct – during the past month, we have observed just six instances of this threat," the researchers wrote. Kaspersky has seen about 80 incidents of the infection reported in the past two years.

Although Narilam is no Stuxnet, it's still destructive. It basically replaces database items with random values, or deletes tables altogether. It's a worm that copies itself to the infected machine and spreads via removable drives and network shares. A few hundred Middle East users have been hit, Symantec's Thakur says.

"The affected organization will likely suffer significant disruption and even financial loss while restoring the database. As the malware is aimed at sabotaging the affected database and does not make a copy of the original database first, those affected by this threat will have a long road to recovery ahead of them," Symantec wrote last week in its original post on the malware.

Security experts concur that Narilam is all about destruction rather than cyberespionage.

"We don't believe this is coming from the same actors behind Stuxnet, Flame, and Duqu. It's not that sophisticated," Thakur says, and there's no cyberespionage link in the malware itself.

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