SNMP Scanning Increase

A multi-vendor SNMPv3 security bug has been found and fixed in Net-SNMP 5.x. It turns out that a lot of vendors suffered the same issues, probably from commonly derived code. Vendors including Juniper, Cisco, and NetApp, among others, have been affected and have made updates available to customers. The bug is in the HMAC digest authentication mechanism that SNMPv3 uses. It reduced the size of the effective authentication digest to 1 byte. So, an attacker can brute force her way across all 256 packets to bypass authentication. Within a couple of days exploit code was available.