What is JA3 hashes?

What is JA3 hashes?

JA3 is a methodology for fingerprinting Transport Layer Security applications. Fingerprinting is achieved by creating a hash of 5 decimal fields of the Client Hello message that is sent in the initial stages of an TLS/SSL session. JA3 is an interesting approach to the increasing usage of encryption in networks.

What is JA3 fingerprinting?

JA3 is a method of fingerprinting the TLS handshake that was first published by John Althouse, Jeff Atkinson, and Josh Atkins from Salesforce back in 2017. Internet traffic which implements TLS will transmit values to each other in an effort to establish a secure connection.

How do I make my TLS 1.2 secure?

1. Open Google Chrome.
2. Click Alt F and select Settings.
3. Scroll down and select Show advanced settings…
4. Scroll down to the Network section and click on Change proxy settings…
5. Select the Advanced tab.
6. Scroll down to Security category, manually check the option box for Use TLS 1.1 and Use TLS 1.2.
7. Click OK.

What can a JA3 hash be used for?

For example, a JA3 hash could be used to identify that Internet Explorer was the application establishing an encrypted connection, but there would be no way to determine if the traffic was a user surfing the internet or malware using Internet Explorer for Command and Control (C2).

Are there any cyber attacks that use JA3?

JA3 is an interesting approach to the increasing usage of encryption in networks. There is also a clear uptick in cyber-attacks using encrypted command and control (C2) channels – such as HTTPS – for malware communication.

What can a JA3 signature be used for?

JA3/S signatures have become a popular Indicator of Compromise (IOC) and have been incorporated into everything from Splunk to advanced IDS/IPS products like Darktrace.

How is JA3 used in SSL fingerprinting?

A new method of TLS fingerprinting was recently put together called JA3. Rather than simply looking at the certificate used, JA3 parses multiple fields set in the TLS client hello packet sent over during the SSL handshake. The resulting fingerprint can then be used to identify, log, alert and/or block specific traffic.