chkrootkit binary package in Ubuntu Lunar amd64

 The chkrootkit security scanner searches for signs that the system is
 infected with a 'rootkit'. Rootkits are a form of malware that seek
 to exploit security flaws to grant unauthorised access to a
 computer or its services, generally for malicious purposes.
 .
 chkrootkit can identify signs of over 70 different rootkits (see the
 project's website for a list).
 .
 Please note that an automated tool like chkrootkit can never
 guarantee a system is uncompromised. Nor does every report always
 signify a genuine problem: human judgement and further investigation
 will always be needed to assure the security of your system.

Source package