Contents
What is the SWEET32 vulnerability?
Description. The Sweet32 attack is a SSL/TLS vulnerability that allows attackers to compromise HTTPS connections using 64-bit block ciphers.
How do I fix SWEET32?
The SWEET32 vulnerability can be resolved by disabling the 3DES cipher still used by Verastream Host Integrator session server. The only one used is TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA and it can be added to the disabledCipherSuites property in the file service-ctx.
Is TLS 1.2 vulnerable to SWEET32?
The SWEET32 (Birthday Attack) is a Medium level vulnerability which is prevalent in TLS 1.0 and TLS 1.1 which support 3DES Encryption. To resolve this issue you should deploy TLS 1.2 as a minimum (the 3DES cypher is dropped by default) and disable vulnerable ciphers.
Can a Blockcipher have collisions?
Encryption algorithms do not produce collisions for the same key. Ever. AES is a block cipher and is built as permutation, The structure of AES is built to ensure that it is indeed a permutation and collision free.
How can you avoid using medium strength ciphers?
To avoid the use of medium strength ciphers, it’ll be necessary to reconfigure the applications that are using them. Most of the application have a parameter to do that. These ciphers should be included in the applications that use SSL negotiation to have high strength ciphers.
Is a block cipher collision resistant?
Collision-resistant compression functions can be built from block ciphers.
Can a TLS variant of Sweet32 be carried out?
Fortunately, successfully carrying out the TLS variant of the Sweet32 attack requires a very particular set of capabilities on the part of the attacker. First, the attacker must be able to execute JavaScript in the victim’s browser. This is so that the attacker can generate data to be sent to the server.
How much data is needed for Sweet32 attack?
Remember, the use of a 64-bit block cipher is likely to produce a collision after 32 GB of data, but for a practical attack the researchers found that up to 785 GB of data is required. Finally, the attacker needs to be in a privileged network position such that they are able to monitor the victim’s encrypted traffic to the web server.
We show that a network attacker who can monitor a long-lived Triple-DES HTTPS connection between a web browser and a website can recover secure HTTP cookies by capturing around 785 GB of traffic. In our proof-of-concept demo, this attack currently takes less than two days, using malicious Javascript to generate traffic.
How many web servers are vulnerable to Sweet32?
The researchers found that 1–2% of all HTTPS web servers use Triple-DES, and even less (0.6%) are configured such that they are vulnerable to this attack. This is admittedly a very small portion of web servers, but some high-profile sites do remain vulnerable: Should I be worried?