Net::NSCA::Client versions through 0.009002 for Perl uses a poor random number generator. Version v0.003 switched to use Data::Rand::Obscure instead of Crypt::Random for generation of a random initialisation vectors. Data::Rand::Obscure uses Perl's built-in rand() function, which is not suitable for cryptographic functions.
https://patch-diff.githubusercontent.com/raw/dougwilson/perl5-net-nsca-client/pull/2.patch