“Researchers have found a new strain of document-based macro malware that evades discovery by lying dormant when it detects a security researcher’s test environment,” reports Threatpost, The Kaspersky Lab security news service. Slashdot reader writes:

Once a computer is compromised, the malware will count the number of Word documents stored on the local drive; if it’s more than two, the malware executes. Otherwise, it figures it’s landed in a virtual environment or is executing in a sandbox and stays dormant.

A typical test environment consists of a fresh Windows computer image loaded into a VM. The OS image usually lacks documents and other telltale signs of real world use [according to SentinelOne researcher Caleb Fenton]. If no Microsoft Word documents are found, the VBA macro’s code execution terminates, shielding the malware from automated analysis and detection. Alternately, if more than two Word documents are found on the targeted system, the macro will download and install the malware payload.

Read more of this story at Slashdot.

Source: Slashdot – Malware Evades Detection By Counting Word Documents