CVE-2017-3738 Information disclosure in OpenSSL
An overflow in OpenSSL's AVX2 Montgomery multiplication may allow attackers to deduce private keys from Diffie-Hellman exchanges, impacting cryptographic security.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2017-3738?
CVE-2017-3738 is a medium-severity vulnerability in Debian Debian Linux, published on 7 Dec 2017. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
There is an overflow bug in the AVX2 Montgomery multiplication procedure used in exponentiation with 1024-bit moduli. No EC algorithms are affected. Analysis suggests that attacks against RSA and DSA as a result of this defect would be very difficult to perform and are not believed likely. Attacks against DH1024 are considered just feasible, because most of the work necessary to deduce information about a private key may be performed offline. The amount of resources required for such an attack would be significant. However, for an attack on TLS to be meaningful, the server would have to share the DH1024 private key among multiple clients, which is no longer an option since CVE-2016-0701. This only affects processors that support the AVX2 but not ADX extensions like Intel Haswell (4th generation). Note: The impact from this issue is similar to CVE-2017-3736, CVE-2017-3732 and CVE-2015-3193. OpenSSL version 1.0.2-1.0.2m and 1.1.0-1.1.0g are affected. Fixed in OpenSSL 1.0.2n. Due to the low severity of this issue we are not issuing a new release of OpenSSL 1.1.0 at this time. The fix will be included in OpenSSL 1.1.0h when it becomes available. The fix is also available in commit e502cc86d in the OpenSSL git repository.
Weakness: CWE-200
Which versions are affected by CVE-2017-3738?
It affects 3 products.
Products include Debian Debian Linux, Nodejs Node.js, Openssl Openssl.
How do I fix CVE-2017-3738?
Upgrade to a fixed version.
Is CVE-2017-3738 being exploited?
There is no known exploitation of CVE-2017-3738 in the wild and no public exploit code.
Other vulnerabilities in Debian Debian Linux
Sources
Also known as ALPINE-CVE-2017-3738, DEBIAN-CVE-2017-3738, GHSA-gj3m-w8pf-46c5, UBUNTU-CVE-2017-3738.