datalenparameter will overflow a data buffer. NTF's
ntpddriver implementations always set this value to 0 and are therefore not vulnerable to this weakness. If you are running a custom refclock driver in
ntpdand that driver supplies a negative value for
datalen(no custom driver of even minimal competence would do this) then
ntpdwould overflow a data buffer. It is even hypothetically possible in this case that instead of simply crashing
ntpdthe attacker could effect a code injection attack.