It indicates an attempt to gain access to a system running Silicon Graphics IRIX operating system via a vulnerability in the lpsched program.
The lpsched program in some versions of IRIX has a vulnerability which allows arbitrary command execution due to improper parsing of shell metacharacters.
IRIX 6.5.13f and earlier
Attackers can execute arbitrary commands on the target system.
Apply appropriate patches or upgrade the system to latest non-vulnerable version.