Signal alerts 1,900 messaging users to a security threat from Twilio hackers

An information breach earlier this month affecting Twilio, a gateway that helps internet platforms talk over SMS or voice, could have had repercussions for customers of Sign, the encrypted messaging platform. Immediately, Sign introduced it has alerted 1,900 customers that their accounts had been doubtlessly revealed to whoever hacked Twilio and stated that the attackers searched for 3 particular numbers in the course of the time that they had entry.

Thus far, Sign says it has heard from a type of three customers that the attackers used their Twilio entry to re-register a brand new machine related to their quantity, which might permit them to ship and obtain messages from that account.

Based on Sign, “message historical past, contact lists, profile info, whom they’d blocked, and different private knowledge” for all customers remained safe. Nonetheless, if somebody was among the many customers doubtlessly revealed, and so they don’t use Sign’s Registration Lock setting that requires their PIN so as to add a brand new machine, then an attacker may’ve re-registered their account.

Sign is sending messages with a hyperlink to its help web page for doubtlessly affected accounts, in addition to unregistering all units linked to these accounts, and stated it will likely be accomplished with this course of by tomorrow.


Lately Twilio, the corporate that gives Sign with cellphone quantity verification providers, suffered a phishing assault. Right here’s what our customers have to know:

All customers can relaxation assured that their message historical past, contact lists, profile info, whom they’d blocked, and different private knowledge stay personal and safe and had been not affected.

For about 1,900 customers, an attacker may have tried to re-register their quantity to a different machine or discovered that their quantity was registered to Sign. This assault has since been shut down by Twilio. 1,900 customers is a really small share of Sign’s whole customers, that means that almost all weren’t affected.

We’re notifying these 1,900 customers straight, and prompting them to re-register Sign on their units. For those who acquired an SMS message from Sign with a hyperlink to this help article, please comply with these steps:

Open Sign in your cellphone and register your Sign account once more if the app prompts you to take action.

To finest shield your account, we strongly suggest that you simply allow registration lock within the app’s Settings. We created this characteristic to guard customers towards threats just like the Twilio assault.