zeek -- potential DoS vulnerabilities

Tim Wojtulewicz of Corelight reports:

Receiving DNS responses from async DNS requests (via the lookup_addr, etc BIF methods) with the TTL set to zero could cause the DNS manager to eventually stop being able to make new requests.

Specially-crafted FTP packets with excessively long usernames, passwords, or other fields could cause log writes to use large amounts of disk space.

The find_all and find_all_ordered BIF methods could take extremely large amounts of time to process incoming data depending on the size of the input.

[source]