A new strain of malware is thrashing corporate databases in the Middle East, claiming the vast majority of its victims in Iran.

Narilam is "causing chaos" by targeting and modifying corporate databases, according to Symantec. The worm spreads through removable drives and network shares.

Network worms are relatively commonplace, but Narilam packs an unusual punch, functionality to update a Microsoft SQL database if it is accessible by OLEDB (Object Linking and Embedding, Database). The worm specifically targets SQL databases with three distinct names: alim, maliran, and shahd.

However Iran's Computer emergency Response Tema said in a statement that the Narilam malware was two years old, "not a major threat" and only corrupted the databases of an unnamed Iranian accountancy software package:

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. 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.

According to Symantec, some of the object/table names that can be accessed by the threat include Hesabjari ("current account" in Arabic/Persian), Asnad (“financial bond” in Arabic), R_DetailFactoreForosh ("forosh" means "sale" in Persian), pasandaz ("savings" in Persian), End_Hesab ("hesab" means "account" in Persian) and Vamghest (“instalment loans” in Persian) as well as tables such as "holiday".

The threat replaces certain items in the database with random values. Some of the items that are modified by the threat include Asnad.SanadNo ("sanad" means "document" in Persian), Asnad.LastNo, Asnad.FirstNo, and Pasandaz.Code (“pasandaz” means “savings” in Persian), refcheck.amount and buyername.Buyername.

Narilam also deletes tables including ones with names including A_Sellers, person and Kalamast.

The malware lacks any functionality to steal information from infected systems and appears to be programmed specifically to damage the data held within the targeted database, Symantec concludes.

"Given the types of objects that the threat searches for, the targeted databases seem to be related to ordering, accounting, or customer management systems belonging to corporations," it adds.

Without well-managed backups, affected databases will be very difficult to restore. The malware is likely to cause significant disruption even if backups are available, according to Symantec. ®