This indicates an attack attempt against an Information Disclosure vulnerability in Eclipse Foundation Jetty Web Server.
The vulnerability is due to improper validation of user supplied data when handling crafted HTTP Requests. A remote attacker can exploit this to disclose sensitive information from affected machines using malicious packets.
Eclipse Foundation Jetty Web Server prior to 9.2.9.v20150224
Information Disclosure: Remote attackers can gain sensitive information from vulnerable systems
Apply the most recent upgrade or patch from the vendor