Security Experts:

CIA Tool 'Pandemic' Replaces Legitimate Files With Malware

Documents published by WikiLeaks on Thursday describe a tool allegedly used by the U.S. Central Intelligence Agency (CIA) to spread malware on a targeted organization’s network.

The tool, named “Pandemic,” installs a file system filter driver designed to replace legitimate files with a malicious payload when they are accessed remotely via the Server Message Block (SMB) protocol.

What makes Pandemic interesting is the fact that it replaces files on-the-fly, instead of actually modifying them on the device the malware is running on. By leaving the legitimate file unchanged, attackers make it more difficult for defenders to identify infected systems.

“Pandemic does NOT//NOT make any physical changes to the targeted file on disk. The targeted file on the system Pandemic is installed on remains unchanged. Users that are targeted by Pandemic, and use SMB to download the targeted file, will receive the 'replacement' file,” the tool’s developers said.

Pandemic, which works on both 32-bit and 64-bit Windows systems, is initially installed on machines from which users download or execute files remotely via SMB. According to the documents leaked by WikiLeaks, the tool can replace up to 20 files at a time – each with a maximum size of 800Mb.

Pandemic developers also provide a DLL file that can be used to determine if the tool is installed, and uninstall it. The files published by WikiLeaks contain information that can be useful for checking a system for Pandemic infections. Experts also pointed out that there is an easy way to see if Pandemic is present on a device.

WikiLeaks has been publishing CIA files, which are part of a leak dubbed “Vault 7,” every Friday since March 23, except for last week. The tools exposed by the whistleblower organization include ones designed for hacking Samsung smart TVs, MitM tools, a framework used to make malware attribution and analysis more difficult, and a platform for creating custom malware installers.

The fact that WikiLeaks delayed last week’s dump until the day the Russian government once again denied interfering with U.S. elections has led some members of the infosec community to believe that the leaks may be timed to serve other purposes, not just to expose the CIA’s activities.

Symantec and Kaspersky have found links between the tools exposed by Wikileaks and the malware used by a cyber espionage group tracked as “Longhorn” and “The Lamberts.”

Related: If the CIA Isnt' Secure, Who Is?

Related: Arrest of WikiLeaks's Assange a 'Priority', Says US Top Cop

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Eduard Kovacs (@EduardKovacs) is a contributing editor at SecurityWeek. He worked as a high school IT teacher for two years before starting a career in journalism as Softpedia’s security news reporter. Eduard holds a bachelor’s degree in industrial informatics and a master’s degree in computer techniques applied in electrical engineering.