CVE-2017-3731

Si un servidor o cliente SSL/TLS se ejecuta en un host de 32 bits y se utiliza un cifrador específico, un paquete truncado puede dar lugar a que el servidor o el cliente realicen una lectura fuera de límites que, normalmente, provoca un cierre inesperado En OpenSSL 1.1.0, el cierre inesperado se puede desencadenar cuando se usa CHACHA20/POLY1305

An integer underflow leading to an out of bounds read flaw was found in OpenSSL. A remote attacker could possibly use this flaw to crash a 32-bit TLS/SSL server or client using OpenSSL if it used the RC4-MD5 cipher suite.

If an SSL/TLS server or client is running on a 32-bit host, and a specific cipher is being used, then a truncated packet can cause that server or client to perform an out-of-bounds read, usually resulting in a crash. There is a carry propagating bug in the x86_64 Montgomery squaring procedure. 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 DH are considered just feasible (although very difficult) 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 very significant and likely only accessible to a limited number of attackers. An 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. Various other issues have also been identified.