Purported CIA documents published by WikiLeaks reveal the U.S. Central Intelligence Agency (CIA) has been hacking wireless routers for years as part of its surveillance efforts.

The trove of documents released by the anti-privacy publication on Thursday details the CIA’s CherryBlossom project, in which the intelligence agency has compromised Wi-Fi routers in private homes, public spaces, businesses and enterprise environments in order to gather information about specific targets.

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The project comes from the CIA's elite hacking unit, the Engineering Development Group. The leaked files include installation guides, manuals and other documents that detail several hacking tools used by the agency to exploit wireless networks.

Once a network is hacked, CherryBlossom allowed CIA agents to monitor the internet activity of a target. They could also redirect the browser, scan for email addresses and phone numbers and carry out a number of software exploits that could further compromise a target’s device.

The “man-in-the-middle” style attack gives the CIA essentially unlimited access to the activity of a user connected to the hacked network—which could potentially include those who aren’t the direct target of the agency.

One of the documents included in the leak documented a number of routers that the CIA had developed tools for to compromise them. About 25 different devices from 10 different manufacturers were included in the list. Among the manufacturers who were listed were Asus, Belkin, D-Link, Linksys and Netgear—all makers of common commercial routers.

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"In general, once a make, model, and hardware version of a device is supported, it is straightforward to implant any later firmware versions, or international firmware versions, so long as the device has not changed its underlying hardware or operating system," the document said.

It is unclear at this time if the exploits detailed in the leak are still active or if they have been retired by the CIA.

The release is the latest from Wikileaks as part of its Vault 7 series, which has focused on releasing leaked documents from the CIA detailing the government agency’s technical capabilities. Previous leaks have shown the intelligence group’s ability to compromise Apple devices, Windows machines, launch malware attacks, and obfuscate the origins of an attack to hide its tracks.  

Routers are a particular point of interest for hackers, be they malicious actors or government agents, because the devices are often hampered by major security flaws and can be compromised remotely without requiring physical interaction.

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Earlier this year, security researchers discovered a number of major vulnerabilities in Linksys routers that made it possible for attackers to target the devices and compromise the internet connection of the user.

In January, the The Federal Trade Commission (FTC) filed a lawsuit against popular router maker D-Link for failing to take steps to properly secure its devices to and leaving consumers vulnerable to hacks and exploits.