criticalWeb server log review · 20 minutes

A file transfer appliance wrote a file to itself

The alert, as it arrived

Web server log review
[04:51:33] FILE INTEGRITY · mft-prod-01 · Severity: Critical
New file in web root, owner = service account, not in deployment manifest

  PATH      C:inetpubwwwrootmoveitisapihuman2.aspx
  SIZE      2,517 bytes
  CREATED   04:51:31
  OWNER     NT SERVICEMOVEit DMZ Web

  Preceding 40 minutes, same source IP, same endpoint:
    04:11:02  POST /moveitisapi/moveitisapi.dll   200   len 1284
    04:11:44  POST /moveitisapi/moveitisapi.dll   200   len 1284
    04:12:19  POST /guestaccess.aspx              200   len 903
    ...  (61 further POSTs, near-identical length)

Your turn

Say what happened, in what order, and what you need to establish before anybody says the word "contained".

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Analyst breakdown

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6 steps in order, each with the reasoning and a runnable query, plus the trap most responders fall into on this one and what the incident actually turns out to be. The scenario above stays free and complete: work it first, and the breakdown is worth more.