Newly released WikiLeaks documents reveal how the CIA can determine the location of a person using a WiFi-enabled Windows PC or laptop.
The program, called ELSA, infects a target Windows machine with malware that leverages the device’s WiFi chipset to scan for nearby public wireless networks and measure their signal strengths. The resulting list of network identifiers and strength data is then compared against large WiFi location databases maintained by companies such as Google and Microsoft to infer the device’s physical location.
ELSA has likely become more accurate over time
This technique is ineffective only when an infected computer lacks a WiFi adapter or when no public wireless signals are within range—situations that are increasingly rare in modern environments.
Although the documents date from 2013 and specifically reference Windows 7, the method is straightforward enough that variants for other Windows versions are believed to exist.
Once the malware produces location information, it encrypts and stores that data so an operative can later decrypt and use it in operations. The leaked files also describe procedures for removing traces of the malware to minimize detection.
This strategy fails when an infected PC doesn’t have WiFi
The full range of ELSA’s capabilities is not fully detailed in the released material, but the malware likely includes additional control features once a system is compromised. In theory, this could allow a disabled WiFi adapter to be reactivated remotely for scanning and data collection.
The leak follows other high-profile disclosures of exploited vulnerabilities stockpiled by intelligence agencies. One such exploit, EternalBlue, was later used in the widespread WannaCry ransomware attack that encrypted systems worldwide and demanded bitcoin payments—including attacks that affected critical health services in the UK. Investigators have discussed possible links between WannaCry and North Korea.
Because public WiFi location databases maintained by major technology companies have expanded and become more detailed since 2013, ELSA’s effectiveness has likely increased correspondingly.
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