DEF CON — A security researcher has revealed severe, now-resolved security vulnerabilities in the Connective digital identity system, a browser extension used by over two million users in Belgium.
Developed by Nitro Software Belgium, the software is used by eight of Belgium’s ten largest banks and over 60 government agencies to manage digital identity authentication and execute legally binding electronic signatures.
James Arnott, security researcher and founder of cybersecurity firm Bay Area Labs, discovered that the software failed to verify which website was attempting to communicate with the user’s computer. Because these checks were missing, any website or embedded online ad could interact directly with the Connective application running on a victim’s machine without their knowledge or permission.
According to Arnott, a malicious website could silently read connected electronic ID (eID) and payment card details. Furthermore, attackers could trick users into revealing their eID PIN by triggering official-looking authentication pop-ups. Because the software allowed web pages to customize the text inside these dialog boxes without displaying the domain making the request, users had no way to verify whether a prompt was legitimate or a phishing attempt.
When a user entered their PIN into a prompt, the application transmitted it back to the requesting webpage. An attacker could then use the PIN to generate unauthorized approval tokens to forge legally binding electronic signatures whenever the victim’s physical eID card was inserted into a card reader.
The compromise of the eID system severely impacted the trust model of Belgium’s broader digital ecosystem, including government portals like CSAM.be and third-party identity providers like Itsme.
While these service providers contained no flaws of their own, their reliance on eID signatures meant that an attacker with stolen signing capabilities could register or hijack digital identity accounts.
In addition to identity theft, the researcher uncovered a remote code execution vulnerability that operated independently of whether an eID card was plugged in. By exploiting a flaw in how the application processed files on the local computer, a malicious website could force the software to execute attacker-controlled code at the user level.
An attacker could execute this drive-by attack by tricking a user into downloading a file disguised as a standard document and visiting a webpage. Requiring no special permissions, the flaw also carried the risk of spreading like a self-propagating worm by hijacking user credentials to send malicious links to other potential victims.
Nitro fully remediated the issues 146 days after the initial report and awarded a $200 bug bounty. The company deployed updates to block unauthorized origin requests and secure PIN handling, with final security enforcement completed in late July. No CVEs appear to have been assigned.
Nitro has not responded to SecurityWeek’s request for comment.
Arnott publicly disclosed the findings at DEF CON and released a blog post with additional technical details.
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