Synopsis
A service running on the remote host is affected by multiple vulnerabilities.
Description
According to its banner, the version of OpenSSL running on the remote host is 1.0.2 prior to 1.0.2k. It is, therefore, affected by multiple vulnerabilities :
- A carry propagation error exists in the Broadwell-specific Montgomery multiplication procedure when handling input lengths divisible by but longer than 256 bits. This can result in transient authentication and key negotiation failures or reproducible erroneous outcomes of public-key operations with specially crafted input. A man-in-the-middle attacker can possibly exploit this issue to compromise ECDH key negotiations that utilize Brainpool P-512 curves. (CVE-2016-7055)
- An out-of-bounds read error exists when handling packets using the CHACHA20/POLY1305 or RC4-MD5 ciphers. An unauthenticated, remote attacker can exploit this, via specially crafted truncated packets, to cause a denial of service condition. (CVE-2017-3731)
- A carry propagating error exists in the x86_64 Montgomery squaring implementation that may cause the BN_mod_exp() function to produce incorrect results. An unauthenticated, remote attacker with sufficient resources can exploit this to obtain sensitive information regarding private keys. Note that this issue is very similar to CVE-2015-3193. Moreover, the attacker would additionally need online access to an unpatched system using the target private key in a scenario with persistent DH parameters and a private key that is shared between multiple clients. For example, this can occur by default in OpenSSL DHE based SSL/TLS cipher suites. (CVE-2017-3732)
Solution
Upgrade to OpenSSL version 1.0.2k or later.