Russian government hackers are targeting Signal and WhatsApp users, particularly government and military officials, as well as journalists all over the world, Dutch intelligence said on Monday.  

The Netherlands’ Defence Intelligence and Security Service (MIVD) and the General Intelligence and Security Service (AIVD) published details about a “large-scale global” hacking campaign against Signal and WhatsApp users. The two agencies accused “Russian state actors” of using phishing and social engineering techniques — rather than malware — to take over accounts on the two messaging apps. 

In the case of Signal, the hackers are masquerading as the app’s support team and messaging targets directly with warnings of suspicious activity, “a possible data leak,” or of attempts to access the target’s private data. If the target falls for it, the hackers ask for a verification code sent via SMS — the hackers themselves request this code from Signal — as well as the targets’ PIN code. 

The hackers then use the verification and PIN codes to register a new device with a new phone number, impersonate the target, and potentially access their contacts, according to the report. Also, the target gets locked out of their account, but can re-register their number.  

“Because Signal stores the chat history locally on the phone, a victim can regain access to that history after re‑registering. As a result, the victim may assume that nothing is wrong. The Dutch services want to stress that this assumption could be incorrect,” the report reads. 

Signal does not provide support directly through the app. And it’s important to note that, generally speaking, when a user adds a new device to their Signal account, the new device does not have access to previous messages. 

Signal did not respond to a request for comment, but posted a thread on social media sharing advice for users on how to protect themselves, including advising against ever sharing the SMS verification code and PIN.

Hackers are also trying to trick targets on both apps into scanning malicious QR codes or clicking on malicious links. “For example, an actor may send a QR code or link to a victim to add them to a chat group, but this QR code or link actually links the actor’s device to the victim’s account,” the report explained. 

In the case of WhatsApp, the hackers are abusing the “Linked devices” function, which allows users to access WhatsApp from a secondary device such as a laptop or a tablet. If the hackers successfully trick their targets, — unlike with Signal — they can potentially read past messages. And sometimes, the victim may not realize that they have granted access to the hackers’ given that they don’t get logged out of their account. 

Meta’s spokesperson Zade Alsawah said that WhatsApp suggests users to never share their six-digit code with anyone, and pointed to a Help Center page to help users recognize suspicious messages, and a page about the Linked Devices feature.

The Dutch Ministry of Interior and Ministry of Defense did not respond to a request for more information about the hacking campaign. 

The Russian embassy in Washington D.C. did not respond to a request for comment. 

Some of the techniques highlighted by the Dutch intelligence services in this report have been known to be used by Russian government hackers in the context of the war against Ukraine.

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