Discovered by persistent bug-hunter Google's Tavis Ormandy. The flaw lies in how the antivirus of the company inspects the encrypted traffic.
Since it decrypts traffic before inspection, Kaspersky presents its certificates as a trusted authority. If a user opens Google on program browsing it, for example, the certificate will appear to come from Kaspersky Anti-Virus Personal Root.
The problem that Ormandy found was that the internal certificates were incredibly weak.
"As new certificates and keys are created, they are entered using the first 32 bits of 3MD5 (serialNumber || issuer) as a key… You do not need to be a cryptographer to understand that a 32bit key is not enough to prevent brute-force attacks" , says the researcher.
Για την αναφορά σφάλματος ο Ormandy έδωσε ένα PoC σύγκρουσης πιστοποιητικών μεταξύ του Chippers News και του manchesterct.gov:
"If you are using Kaspersky Antivirus in Manchester, and you are wondering why Hacker News does not work sometimes, it is because a critical vulnerability has disabled SSL authentication for 400 million Kaspersky users."
Kaspersky reportedly corrected the 28 December error.