CVE-2022-40735 Denial of service in n/a
Attackers can cause server-side resource exhaustion and denial of service by exploiting inefficient Diffie-Hellman key agreement calculations.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2022-40735?
CVE-2022-40735 is a high-severity denial of service vulnerability in n/a, published on 14 Nov 2022. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
The Diffie-Hellman Key Agreement Protocol allows use of long exponents that arguably make certain calculations unnecessarily expensive, because the 1996 van Oorschot and Wiener paper found that "(appropriately) short exponents" can be used when there are adequate subgroup constraints, and these short exponents can lead to less expensive calculations than for long exponents. This issue is different from CVE-2002-20001 because it is based on an observation about exponent size, rather than an observation about numbers that are not public keys. The specific situations in which calculation expense would constitute a server-side vulnerability depend on the protocol (e.g., TLS, SSH, or IKE) and the DHE implementation details. In general, there might be an availability concern because of server-side resource consumption from DHE modular-exponentiation calculations. Finally, it is possible for an attacker to exploit this vulnerability and CVE-2002-20001 together.
Weakness: CWE-400
Which versions are affected by CVE-2022-40735?
It affects 1 product.
Products include Diffie-Hellman Key Exchange Project Diffie-Hellman Key Exchange.
How do I fix CVE-2022-40735?
Apply the vendor's patch.
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-2022-40735 being exploited?
There is no known exploitation of CVE-2022-40735 in the wild and no public exploit code.
Sources
Also known as GHSA-8vmc-7qrc-q5mx, UBUNTU-CVE-2022-40735, USN-6854-1.