Detection rules › Kusto

Corelight - Multiple Compressed Files Transferred over HTTP

Status
available
Severity
medium
Time window
15m
Group by
id_orig_h, uri
Source
github.com/Azure/Azure-Sentinel

'Detects compressed archives transferre over HTTP.'

MITRE ATT&CK coverage

TacticTechniques
ExfiltrationT1567 Exfiltration Over Web Service

Rule body kusto

id: 4e55e306-3022-43a1-870a-41c4d5116079
name: Corelight - Multiple Compressed Files Transferred over HTTP
description: |
  'Detects compressed archives transferre over HTTP.'
severity: Medium
status: Available
requiredDataConnectors:
  - connectorId: Corelight
    dataTypes:
      - Corelight_v2_http
      - corelight_http
queryFrequency: 1h
queryPeriod: 1h
triggerOperator: gt
triggerThreshold: 0
tactics:
  - Exfiltration
relevantTechniques:
  - T1567
query: |
  let threshold = 25;
  corelight_http
  | where method in~ ('POST', 'PUT')
  | where isempty(referrer)
  | where orig_mime_types has_any ('application/vnd.ms-cab-compressed', 'application/warc', 'application/x-7z-compressed', 'application/x-ace', 'application/x-arc', 'application/x-archive', 'application/x-arj', 'application/x-compress', 'application/x-cpio', 'application/x-dmg', 'application/x-eet', 'application/x-gzip', 'application/x-lha', 'application/x-lrzip', 'application/x-lz4', 'application/x-lzma', 'application/x-lzh', 'application/x-lzip', 'application/x-rar', 'application/x-rpm', 'application/x-stuffit', 'application/x-tar', 'application/x-xz', 'application/x-zoo', 'application/zip')
  | summarize count() by uri, id_orig_h, bin(TimeGenerated, 15m)
  | where count_ > threshold
entityMappings:
  - entityType: IP
    fieldMappings:
      - identifier: Address
        columnName: id_orig_h
version: 2.1.1
kind: Scheduled

Stages and Predicates

Parameters

let threshold = 25;

Stage 1: source

corelight_http

Stage 2: where

| where method in~ ('POST', 'PUT')

Stage 3: where

| where isempty(referrer)

Stage 4: where

| where orig_mime_types has_any ('application/vnd.ms-cab-compressed', 'application/warc', 'application/x-7z-compressed', 'application/x-ace', 'application/x-arc', 'application/x-archive', 'application/x-arj', 'application/x-compress', 'application/x-cpio', 'application/x-dmg', 'application/x-eet', 'application/x-gzip', 'application/x-lha', 'application/x-lrzip', 'application/x-lz4', 'application/x-lzma', 'application/x-lzh', 'application/x-lzip', 'application/x-rar', 'application/x-rpm', 'application/x-stuffit', 'application/x-tar', 'application/x-xz', 'application/x-zoo', 'application/zip')

Stage 5: summarize

| summarize count() by uri, id_orig_h, bin(TimeGenerated, 15m)

Stage 6: where

| where count_ > threshold

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

FieldKindValues
count_gt
  • 25 transforms: cased
methodin
  • POST
  • PUT
orig_mime_typesmatch
  • application/vnd.ms-cab-compressed
  • application/warc
  • application/x-7z-compressed
  • application/x-ace
  • application/x-arc
  • application/x-archive
  • application/x-arj
  • application/x-compress
  • application/x-cpio
  • application/x-dmg
  • application/x-eet
  • application/x-gzip
  • application/x-lha
  • application/x-lrzip
  • application/x-lz4
  • application/x-lzh
  • application/x-lzip
  • application/x-lzma
  • application/x-rar
  • application/x-rpm
  • application/x-stuffit
  • application/x-tar
  • application/x-xz
  • application/x-zoo
  • application/zip
referreris_null
  • (no value, null check)

Output fields

Fields the rule emits when it matches. Chronicle authors list these in the outcome block; they appear on the detection and $risk_score drives alerting. Sentinel / Defender XDR rules build them up through project / summarize / extend stages. Sentinel maps these into alert fields via entityMappings and customDetails; Defender XDR custom detections surface them as alert fields directly.

FieldSource
id_orig_hsummarize
urisummarize