HAFNIUM Exchange Exploitation Activity

Status: test
Severity: critical
Log source: product windows, category process_creation
Author: Florian Roth (Nextron Systems)
Source: github.com/SigmaHQ/sigma

Detects activity observed by different researchers to be HAFNIUM group activity (or related) on Exchange servers

MITRE ATT&CK coverage

Tactic	Techniques
Execution	`T1053` Scheduled Task/Job
Persistence	`T1053` Scheduled Task/Job, `T1546` Event Triggered Execution
Privilege Escalation	`T1053` Scheduled Task/Job, `T1546` Event Triggered Execution

Event coverage

Provider	Event	Title
Sysmon	Event ID 1	Process creation
Security-Auditing	Event ID 4688	A new process has been created.

Rule body yaml

title: HAFNIUM Exchange Exploitation Activity
id: bbb2dedd-a0e3-46ab-ba6c-6c82ae7a9aa7
status: test
description: Detects activity observed by different researchers to be HAFNIUM group activity (or related) on Exchange servers
references:
    - https://blog.truesec.com/2021/03/07/exchange-zero-day-proxylogon-and-hafnium/
    - https://www.microsoft.com/security/blog/2021/03/02/hafnium-targeting-exchange-servers/
    - https://discuss.elastic.co/t/detection-and-response-for-hafnium-activity/266289/3
    - https://twitter.com/GadixCRK/status/1369313704869834753?s=20
    - https://twitter.com/BleepinComputer/status/1372218235949617161
author: Florian Roth (Nextron Systems)
date: 2021-03-09
modified: 2023-03-09
tags:
    - attack.privilege-escalation
    - attack.execution
    - attack.persistence
    - attack.t1546
    - attack.t1053
    - attack.g0125
    - detection.emerging-threats
logsource:
    category: process_creation
    product: windows
detection:
    selection_attrib:
        CommandLine|contains|all:
            - 'attrib'
            - ' +h '
            - ' +s '
            - ' +r '
            - '.aspx'
    selection_vsperfmon:
        - Image|contains: '\ProgramData\VSPerfMon\'
        - CommandLine|contains|all:
              - 'schtasks'
              - 'VSPerfMon'
    selection_opera_1:
        Image|endswith: 'Opera_browser.exe'
        ParentImage|endswith:
            - '\services.exe'
            - '\svchost.exe'
    selection_opera_2:
        Image|endswith: 'Users\Public\opera\Opera_browser.exe'
    selection_vssadmin:
        CommandLine|contains|all:
            - 'vssadmin list shadows'
            - 'Temp\__output'
    selection_makecab_1:
        Image|endswith: '\makecab.exe'
        CommandLine|contains|all:
            - 'inetpub\wwwroot\'
            - '.dmp.zip'
    selection_makecab_2:
        Image|endswith: '\makecab.exe'
        CommandLine|contains:
            - 'Microsoft\Exchange Server\'
            - 'compressionmemory'
            - '.gif'
    selection_7zip:
        CommandLine|contains|all:
            - ' -t7z '
            - 'C:\Programdata\pst'
            - '\it.zip'
    selection_rundll32:
        CommandLine|contains|all:
            - '\comsvcs.dll'
            - 'Minidump'
            - 'full '
            - '\inetpub\wwwroot'
    selection_other:
        CommandLine|contains:
            - 'Windows\Temp\xx.bat'
            - 'Windows\WwanSvcdcs'
            - 'Windows\Temp\cw.exe'
    condition: 1 of selection*
falsepositives:
    - Unlikely
level: critical

Stages and Predicates

Stage 0: `condition`

1 of selection*

Stage 1: `selection_attrib`

selection_attrib:
    CommandLine|contains|all:
        - 'attrib'
        - ' +h '
        - ' +s '
        - ' +r '
        - '.aspx'

Stage 2: `selection_vsperfmon`

selection_vsperfmon:
    - Image|contains: '\ProgramData\VSPerfMon\'
    - CommandLine|contains|all:
          - 'schtasks'
          - 'VSPerfMon'

Stage 3: `selection_opera_1`

selection_opera_1:
    Image|endswith: 'Opera_browser.exe'
    ParentImage|endswith:
        - '\services.exe'
        - '\svchost.exe'

Stage 4: `selection_opera_2`

selection_opera_2:
    Image|endswith: 'Users\Public\opera\Opera_browser.exe'

Stage 5: `selection_vssadmin`

selection_vssadmin:
    CommandLine|contains|all:
        - 'vssadmin list shadows'
        - 'Temp\__output'

Stage 6: `selection_makecab_1`

selection_makecab_1:
    Image|endswith: '\makecab.exe'
    CommandLine|contains|all:
        - 'inetpub\wwwroot\'
        - '.dmp.zip'

Stage 7: `selection_makecab_2`

selection_makecab_2:
    Image|endswith: '\makecab.exe'
    CommandLine|contains:
        - 'Microsoft\Exchange Server\'
        - 'compressionmemory'
        - '.gif'

Stage 8: `selection_7zip`

selection_7zip:
    CommandLine|contains|all:
        - ' -t7z '
        - 'C:\Programdata\pst'
        - '\it.zip'

Stage 9: `selection_rundll32`

selection_rundll32:
    CommandLine|contains|all:
        - '\comsvcs.dll'
        - 'Minidump'
        - 'full '
        - '\inetpub\wwwroot'

Stage 10: `selection_other`

selection_other:
    CommandLine|contains:
        - 'Windows\Temp\xx.bat'
        - 'Windows\WwanSvcdcs'
        - 'Windows\Temp\cw.exe'

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.

Field	Kind	Values
`CommandLine`	match	`+h` corpus 2 (sigma 2) `+r` `+s` corpus 2 (sigma 2) `-t7z` `.aspx` corpus 2 (sigma 2) `.dmp.zip` `.gif` corpus 8 (sigma 8) `C:\Programdata\pst` `Microsoft\Exchange Server\` `Minidump` corpus 5 (sigma 4, chronicle 1) `Temp\__output` `VSPerfMon` `Windows\Temp\cw.exe` `Windows\Temp\xx.bat` `Windows\WwanSvcdcs` `\comsvcs.dll` `\inetpub\wwwroot` `\it.zip` `attrib` `compressionmemory` `full` `inetpub\wwwroot\` `schtasks` corpus 6 (sigma 5, kusto 1) `vssadmin list shadows` corpus 2 (sigma 2)
`Image`	ends_with	`Opera_browser.exe` `Users\Public\opera\Opera_browser.exe` `\makecab.exe` corpus 5 (sigma 5)
`Image`	match	`\ProgramData\VSPerfMon\`
`ParentImage`	ends_with	`\services.exe` corpus 8 (sigma 8) `\svchost.exe` corpus 14 (sigma 14)

`j` / `k`	Scroll down / up
`d` / `u`	Half-page down / up
`gg` / `G`	Top / bottom
`h` / `l`	History back / forward
`f`	Follow link (`Shift` = new tab)
`/`	Focus search
`?`	Toggle this help
`↑` / `↓`	Navigate search results
`Enter`	Open highlighted result
`Esc`	Close results / dialog

`type:`	`events` / `rules` / `providers`
`vendor:`	`sigma` / `elastic` / `splunk` / `kusto` / `chronicle` (vendor name alone also works: `sigma:`, `kql:`, `secops:`…)
`tactic:`	TA-id, slug, or name: `credential_access`, `TA0006`
`technique:`	technique or sub-technique ID: `T1003`, `T1003.001` (alias `tech:`)
`severity:`	`critical` / `high` / `medium` / `low` / `informational` (alias `sev:`)
`risk_score`	Numeric comparison on the Elastic risk score (0 to 100): `risk_score>50`, `risk_score<=20`, `risk_score=99` (alias `risk`; Elastic rules only)
`stages:`	Rules with exactly N pipeline stages
`correlation:`	`single_event` / `sequence` / `alternatives` / `alternatives_cross_log` / `all_required` / `correlated`
`with:`	Co-occurrence event-id; stacks (`with:4624 with:4769`) to require all, while a comma list in one occurrence (`with:4624,4769`) is an either-or group. Implies multi-event
`like:`	Structural neighbors of a rule slug (equivalents + subsumption stricter / broader): `like:comsvcs_lsass_memory_dump-splunk-sysmon`
`groupby:`	Entity-grouping substring match against `group_by_keys`: `groupby:user`, `groupby:host`
`uses:`	Rules whose predicate tree touches the field (any kind, any value): `uses:CommandLine`
`excludes:`	Rules with top-level `not()` clauses on the field (FP whitelists): `excludes:ParentImage`
`field:` / `value:`	Predicate search; narrows rule cards to those with a matching leaf and drives the indicator tier. Unquoted = substring, wildcards allowed (`value:mimikatz`)
`indicator:`	Shorthand for `field:F value:V`: `indicator:Image=*\powershell.exe`
`kind:`	Filter by predicate kind. Narrows rule cards to those carrying a matching predicate leaf (`vendor:elastic kind:cidr_match`) and drives the indicator tier: `contains` / `starts_with` / `ends_with` / `regex` / `cidr` / `eq` / `in` … (operator aliases `op:`/`match:`)
`has:` / `no:`	`sample`, `field`, `notes`, `refs`, `trace`, `thirdparty`, `rule`, `pattern`, `timewindow`, `threshold`, `newterms`, `sigma`/`elastic`/`splunk`/`kusto`/`chronicle`
`-op:val`	Exclude matches; works on most operators but not `type:`/`like:`/`has:`/`no:` (use `no:<flag>` to exclude a rule flag): `tactic:execution -vendor:splunk`. Standalone `-kind:`/`-field:`/`-value:` drop every rule carrying a matching predicate leaf (`type:rules -kind:is_null`)
`field:"…"` / `value:"…"`	Quoted value = anchored exact match (also allows spaces): `value:"net user"`
`a,b`	Comma = OR inside one operator (`vendor:sigma,elastic`, `severity:high,critical`); repeating a facet merges the same way. `field:`/`value:` never split (literal commas)
`vendors:` / `stage:`	Singular and plural spellings fold to the canonical operator and value: `tactics:` = `tactic:`, `type:event` = `type:events`, `correlation:sequences` = `correlation:sequence`, `has:thresholds` = `has:threshold`
`"quoted phrase"`	Exact-match a multi-word phrase (free text)

HAFNIUM Exchange Exploitation Activity

MITRE ATT&CK coverage

Event coverage

Rule body yaml

Stages and Predicates

Stage 0: `condition`

Stage 1: `selection_attrib`

Stage 2: `selection_vsperfmon`

Stage 3: `selection_opera_1`

Stage 4: `selection_opera_2`

Stage 5: `selection_vssadmin`

Stage 6: `selection_makecab_1`

Stage 7: `selection_makecab_2`

Stage 8: `selection_7zip`

Stage 9: `selection_rundll32`

Stage 10: `selection_other`

Indicators

Keyboard shortcuts

Search operators

HAFNIUM Exchange Exploitation Activity

MITRE ATT&CK coverage

Event coverage

Rule body yaml

Stages and Predicates

Stage 0: condition

Stage 1: selection_attrib

Stage 2: selection_vsperfmon

Stage 3: selection_opera_1

Stage 4: selection_opera_2

Stage 5: selection_vssadmin

Stage 6: selection_makecab_1

Stage 7: selection_makecab_2

Stage 8: selection_7zip

Stage 9: selection_rundll32

Stage 10: selection_other

Indicators

Stage 0: `condition`

Stage 1: `selection_attrib`

Stage 2: `selection_vsperfmon`

Stage 3: `selection_opera_1`

Stage 4: `selection_opera_2`

Stage 5: `selection_vssadmin`

Stage 6: `selection_makecab_1`

Stage 7: `selection_makecab_2`

Stage 8: `selection_7zip`

Stage 9: `selection_rundll32`

Stage 10: `selection_other`