Researchers Exploit Flaws in Browser SSL/TLS Encryption

Two security researchers say they have poked holes in the secure sockets layer (SSL) and transport layer security (TLS) protocol with a new tool that enables attackers to decrypt HTTP cookies.

During their upcoming presentation at the Ekoparty conference in Buenos Aires, security researchers Juliano Rizzo and Thai Duong are slated to release a tool they have dubbed “BEAST” – Browser Exploit Against SSL/TLS. According to reports, the two exploit a known vulnerability that, unlike other SSL attacks, is based on an implementation flaw and not in the digital certificate model.

“We present a new fast block-wise chosen-plaintext attack against SSL/TLS,” the two wrote in their description of their work on the Ekoparty Website. “We also describe one application of the attack that allows an adversary to efficiently decrypt and obtain authentication tokens and cookies from HTTPS requests. Our exploit abuses a vulnerability present in the SSL/TLS implementation of major Web browsers at the time of writing.”

“While other attacks focus on the authenticity property of SSL, BEAST attacks the confidentiality of the protocol,” Duong reportedly told Threatpost in an interview. “As far as we know, BEAST implements the first attack that actually decrypts HTTPS requests. While fixing the authenticity vulnerabilities may require a new trust model, fixing the vulnerability that BEAST exploits may require a major change to the protocol itself. Actually we have worked with browser and SSL vendors since early May, and every single proposed fix is incompatible with some existing SSL applications.”

According to reports, the attack impacts TLS 1.0 and SSL 3.0, but does not affect TLS versions 1.1 and 1.2. Duong and Rizzo are scheduled to release their findings on Friday.