There are more POODLEs in the forest

In December it was announced that several TLS server implementations were affected by a problem similar to an SSL v3 issue called POODLE disclosed by Google researchers in October. This attack worked by modifying the padding bytes of the encrypted SSL/TLS records that are used to make the records into even multiples of 8 or 16 byte blocks of data, checking how the server responded, and used this to deduce the plain text of the transmitted data, one byte at a time, with just a few tries.

Several major vendors were affected by the TLS variant of the POODLE issue, and released patches. Continue reading «There are more POODLEs in the forest»

The POODLE has friends

In October last year, researchers from Google published details about an attack on SSL v3, called POODLE. This attack worked by modifying the padding bytes of the encrypted SSL records that are used to make the records into even multiples of 8 or 16 byte blocks of data, as used by 3DES and AES encryption in the «CBC» mode, checking how the server responded, and used this to deduce the plain text of the transmitted data, one byte at a time, with just a few tries. Continue reading «The POODLE has friends»

Usikker registrering av persondata i mange nettbutikker

[Apologies to my English language readers, as this article mainly concerns encryption in Norwegian online shopping sites, I decided to write it in Norwegian]

Jeg har ved at par tidligere anledninger undersøkt bruken av kryptering av norske nettbutikker, sist i 2013. Konklusjonen begge ganger har vært at kryptering er lite brukt.

I løpet av januar gjennomførte jeg en ny undersøkelse av kryptering i norske nettbutikker. I tillegg til 59 butikker jeg hadde undersøkt tidligere, inkluderte jeg denne gangen 184 nye nettbutikker fra Posten.no‘s liste over nettbutikker, totalt 243 butikker.  Continue reading «Usikker registrering av persondata i mange nettbutikker»

Not out of the woods yet: There are more POODLEs

As I wrote in my previous article about this, in October a group of Google security researchers had discovered a problem, called POODLE, in SSL v3 that in combination with another issue, browsers’ automatic fallback to older TLS and SSL versions, allowed an attacker to quickly break the encryption of sensitive content, like cookies.

The main mitigating methods for this problem are disabling SSL v3 support, both server side (now down to 66.2%, but slowing down) and in the client, and to limit the automatic fallback, either by not falling back to SSL v3 (which is now implemented by several browsers), or by a new method called TLS_FALLBACK_SCSV (introduced by Google Chrome and others). Continue reading «Not out of the woods yet: There are more POODLEs»

Attack of the POODLEs

Three weeks ago a group of researchers from Google announced an attack against the SSL v3 protocol (the ancestor of the TLS 1.x protocol) called POODLE (a stylish abbreviation of «Padding Oracle On Downgraded Legacy Encryption»). This attack is similar to the BEAST attack that was revealed a few years ago, and one of the researchers that found the POODLE attack was part of the team that found BEAST.

POODLE is able to quickly discover the content of a HTTPS request, such as a session cookie, but only if the connection is using the SSL v3 protocol, a version of SSL/TLS that became obsolete with the introduction of TLS 1.0 in 1999. As almost all (>99%) secure web servers now support at least TLS 1.0 (which is not vulnerable to the attack, provided the server is correctly implemented), it might sound like this attack is not very useful. Unfortunately, that is not so. Continue reading «Attack of the POODLEs»

What is tls-testing.tlsprober.net?

Executive summary: The TLS Prober is a tool that gathers information and statistics about the state of the SSL/TLS protocol security features and vulnerabilities across the internet. It does nothing that will harm your server.

The TLS Prober is a tool I developed while I worked I worked at Opera Software, originally to track the progress of the TLS Renego problem, and which I was allowed to take with me when I left Opera in early 2013. It is primarily used to scan a set of 23 million hostnames, most of the names derived from Alexa top million domain names, resulting in tests of about 500000 unique servers, for their support of SSL and TLS features, as well as checking for various interoperability issues and vulnerabilities.

Similar tools are also in use by others, such as the Qualys SSL Labs prober. Continue reading «What is tls-testing.tlsprober.net?»