Detection rules › Sigma

CVE-2020-0688 Exchange Exploitation via Web Log

Status
test
Severity
critical
Log source
category webserver
Author
Florian Roth (Nextron Systems)
Source
github.com/SigmaHQ/sigma

Detects the exploitation of Microsoft Exchange vulnerability as described in CVE-2020-0688

MITRE ATT&CK coverage

TacticTechniques
Initial AccessT1190 Exploit Public-Facing Application

Rule body yaml

title: CVE-2020-0688 Exchange Exploitation via Web Log
id: fce2c2e2-0fb5-41ab-a14c-5391e1fd70a5
status: test
description: Detects the exploitation of Microsoft Exchange vulnerability as described in CVE-2020-0688
references:
    - https://www.trustedsec.com/blog/detecting-cve-20200688-remote-code-execution-vulnerability-on-microsoft-exchange-server/
author: Florian Roth (Nextron Systems)
date: 2020-02-29
modified: 2023-01-02
tags:
    - attack.initial-access
    - attack.t1190
    - cve.2020-0688
    - detection.emerging-threats
logsource:
    category: webserver
detection:
    selection1:
        cs-method: 'GET'
        cs-uri-query|contains:
            - '/ecp/'
            - '/owa/'
    selection2:
        cs-uri-query|contains: '__VIEWSTATE='
    condition: all of selection*
falsepositives:
    - Unknown
level: critical

Stages and Predicates

Stage 0: condition

all of selection*

Stage 1: selection1

selection1:
    cs-method: 'GET'
    cs-uri-query|contains:
        - '/ecp/'
        - '/owa/'

Stage 2: selection2

selection2:
    cs-uri-query|contains: '__VIEWSTATE='

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
cs-methodeq
  • GET
cs-uri-querymatch
  • /ecp/
  • /owa/
  • __VIEWSTATE=