CVE-2017-3733 Encrypt-Then-Mac renegotiation crash
A crash in OpenSSL during renegotiation when Encrypt-Then-Mac settings mismatch causes denial of service for clients and servers.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2017-3733?
CVE-2017-3733 is a high-severity denial of service vulnerability in Openssl Openssl, published on 4 May 2017. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
During a renegotiation handshake if the Encrypt-Then-Mac extension is negotiated where it was not in the original handshake (or vice-versa) then this can cause OpenSSL 1.1.0 before 1.1.0e to crash (dependent on ciphersuite). Both clients and servers are affected.
Weakness: CWE-20
Which versions are affected by CVE-2017-3733?
It affects 2 products.
Products include Hp Operations Agent, Openssl Openssl.
How do I fix CVE-2017-3733?
Upgrade to a fixed version.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2017-3733 being exploited?
There is no known exploitation of CVE-2017-3733 in the wild and no public exploit code.
Other vulnerabilities in Openssl Openssl
Sources
Also known as DEBIAN-CVE-2017-3733, GHSA-6553-6v42-5wqc.