SSL 64-bit Block Size Cipher Suites Supported (SWEET32)

Low Nessus Network Monitor Plugin ID 7222

Synopsis

The remote host supports the use of 64-bit block ciphers.

Description

The remote host supports the use of a block cipher with 64-bit blocks in one or more cipher suites. It is, therefore, affected by a vulnerability, known as SWEET32, due to the use of weak 64-bit block ciphers. A man-in-the-middle attacker who has sufficient resources can exploit this vulnerability, via a 'birthday' attack, to detect a collision that leaks the XOR between the fixed secret and a known plaintext, allowing the disclosure of the secret text, such as secure HTTPS cookies, and possibly resulting in the hijacking of an authenticated session. Proof-of-concepts have shown that attackers can recover authentication cookies from an HTTPS session in as little as 30 hours. Note that the ability to send a large number of requests over the same TLS connection between the client and server is an important requirement for carrying out this attack. If the number of requests allowed for a single connection were limited, this would mitigate the vulnerability.

Solution

Reconfigure the affected application, if possible, to avoid use of all 64-bit block ciphers. Alternatively, place limitations on the number of requests that are allowed to be processed over the same TLS connection to mitigate this vulnerability.

See Also

https://sweet32.info

http://www.nessus.org/u?8891df96

http://www.nessus.org/u?dcd90dc3

https://www.openssl.org/blog/blog/2016/08/24/sweet32

Plugin Details

Severity: Low

ID: 7222

Version: 1.0

Family: Generic

Published: 2016/08/24

Modified: 2018/08/16

Risk Information

Risk Factor: Low

CVSSv2

Base Score: 2.6

Temporal Score: 2.5

Vector: CVSS2#AV:N/AC:H/Au:N/C:P/I:N/A:N

Temporal Vector: CVSS2#E:F/RL:ND/RC:C

Vulnerability Information

Patch Publication Date: 2016/08/24

Vulnerability Publication Date: 2016/08/24