I've started seeing these lines in my daily logs.  Don't recall when they started, but I know for 2 days now.  Can someone explain why they are "false" ?

--------------------- "pam_unix" = false Begin ------------------------ 

crond:
   Unknown Entries:
      session closed for user root: 170 Time(s)
      session opened for user root by (uid=0): 170 Time(s)
      session closed for user rob: 40 Time(s)
      session opened for user rob by (uid=0): 40 Time(s)

rsh:
   Unknown Entries:
      session closed for user rob: 2 Time(s)
      session opened for user rob by (uid=0): 2 Time(s)

sshd:
   Authentication Failures:
      root (200.55.192.29): 3 Time(s)
      unknown (211.233.38.86): 3 Time(s)
      unknown (152.92.112.120): 2 Time(s)
      unknown (218.206.92.226): 2 Time(s)
   Invalid Users:
      Unknown Account: 7 Time(s)

su:
   Sessions Opened:
      sam(uid=500) -> root: 2 Time(s)


 ---------------------- "pam_unix" = false End -------------------------
Snowman