This indicates a possible exploit of a buffer-overflow vulnerability in the Snort Back Orifice Preprocessor.
The vulnerability is due to the Snort Back Orifice Preprocessor's failure to properly sanitize data received from the network, leading to system compromise if it is successfully exploited. A remote attacker may execute arbitrary code on a vulnerable system by sending crafted UDP packets to the SNORT sensor.
Snort 2.4.0 (April 2005), Snort 2.4.1 and Snort 2.4.2
Apply the appropriate patch from the vendor.