fetchmail -- chosen plaintext attack against SSL CBC initialization vectors

Matthias Andree reports:

Fetchmail version 6.3.9 enabled "all SSL workarounds" (SSL_OP_ALL) which contains a switch to disable a countermeasure against certain attacks against block ciphers that permit guessing the initialization vectors, providing that an attacker can make the application (fetchmail) encrypt some data for him -- which is not easily the case.

Stream ciphers (such as RC4) are unaffected.

Credits to Apple Product Security for reporting this.

[source]