Sigma rule: Suspicious MSExchangeMailboxReplication ASPX Write

A detection rule from the SigmaHQ repository, shown as its author published it. Dataset version ref-9c4b15985ba8, updated 2022-02-25T00:00:00.000Z.

Rule

Title
Suspicious MSExchangeMailboxReplication ASPX Write
Status
test
Level
high
Author
Florian Roth (Nextron Systems)
Date
2022-02-25
File
rules/windows/file/file_event/file_event_win_susp_exchange_aspx_write.yml
Commit
ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects suspicious activity in which the MSExchangeMailboxReplication process writes .asp and .apsx files to disk, which could be a sign of ProxyShell exploitation

Log source

product
windows
category
file_event

Detection

selection:
    Image|endswith: '\MSExchangeMailboxReplication.exe'
    TargetFilename|endswith:
        - '.aspx'
        - '.asp'
condition: selection

False positives (as the rule lists them)

  • Unknown

Tags

  • attack.initial-access
  • attack.t1190
  • attack.persistence
  • attack.t1505.003

MITRE ATT&CK ids this rule names

References

Read on 2026-11-03T00:58:21.399Z under licence sigma-drl-1.1@d5f4c36a from https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules/windows/file/file_event/file_event_win_susp_exchange_aspx_write.yml

Sources and licences

  • SigmaHQ

    "Suspicious MSExchangeMailboxReplication ASPX Write" by Florian Roth (Nextron Systems) (SigmaHQ). Rule: https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules/windows/file/file_event/file_event_win_susp_exchange_aspx_write.yml.
    Licensed under the Detection Rule License (DRL) 1.1: https://github.com/SigmaHQ/Detection-Rule-License

    Detection Rule License (DRL) 1.1

Cite this page

Dragons Eye Ransomware Tracker, "Sigma rule: Suspicious MSExchangeMailboxReplication ASPX Write",
entity page, dataset version ref-9c4b15985ba8, updated 2022-02-25T00:00:00.000Z,
https://ransomware-tracker.com/detections/sigma/7280c9f3-a5af-45d0-916a-bc01cb4151c9 (accessed 2026-11-03).
Underlying source: SigmaHQ rule 7280c9f3-a5af-45d0-916a-bc01cb4151c9, commit ccbb0369507f796db0b0ae6854c8a2be471b9d84.

Pages change. The dataset version identifies the data, but no archive of old versions is kept, so this citation cannot be replayed later.