Always Install Elevated Windows Installer

Status: test
Severity: medium
Log source: product windows, category process_creation
Author: Teymur Kheirkhabarov (idea), Mangatas Tondang (rule), oscd.community
Source: github.com/SigmaHQ/sigma

Detects Windows Installer service (msiexec.exe) trying to install MSI packages with SYSTEM privilege

MITRE ATT&CK coverage

Tactic	Techniques
Privilege Escalation	`T1548.002` Abuse Elevation Control Mechanism: Bypass User Account Control

Event coverage

Provider	Event	Title
Sysmon	Event ID 1	Process creation

Rule body yaml

title: Always Install Elevated Windows Installer
id: cd951fdc-4b2f-47f5-ba99-a33bf61e3770
status: test
description: Detects Windows Installer service (msiexec.exe) trying to install MSI packages with SYSTEM privilege
references:
    - https://image.slidesharecdn.com/kheirkhabarovoffzonefinal-181117201458/95/hunting-for-privilege-escalation-in-windows-environment-48-638.jpg
author: Teymur Kheirkhabarov (idea), Mangatas Tondang (rule), oscd.community
date: 2020-10-13
modified: 2024-12-01
tags:
    - attack.privilege-escalation
    - attack.t1548.002
logsource:
    product: windows
    category: process_creation
detection:
    selection_user:
        User|contains: # covers many language settings
            - 'AUTHORI'
            - 'AUTORI'
    selection_image_1:
        Image|contains|all:
            - '\Windows\Installer\'
            - 'msi'
        Image|endswith: 'tmp'
    selection_image_2:
        Image|endswith: '\msiexec.exe'
        IntegrityLevel:
            - 'System'
            - 'S-1-16-16384'
    filter_installer:
        ParentImage: 'C:\Windows\System32\services.exe'
    filter_repair:
        - CommandLine|endswith: '\system32\msiexec.exe /V' # ignore "repair option"
        - ParentCommandLine|endswith: '\system32\msiexec.exe /V' # ignore "repair option"
    filter_sophos:
        ParentImage|startswith: 'C:\ProgramData\Sophos\'
    filter_avira:
        ParentImage|startswith: 'C:\ProgramData\Avira\'
    filter_avast:
        ParentImage|startswith:
            - 'C:\Program Files\Avast Software\'
            - 'C:\Program Files (x86)\Avast Software\'
    filter_google_update:
        ParentImage|startswith:
            - 'C:\Program Files\Google\Update\'
            - 'C:\Program Files (x86)\Google\Update\'
    condition: 1 of selection_image_* and selection_user and not 1 of filter_*
falsepositives:
    - System administrator usage
    - Anti virus products
    - WindowsApps located in "C:\Program Files\WindowsApps\"
level: medium

Stages and Predicates

Stage 0: `condition`

1 of selection_image_* and selection_user and not 1 of filter_*

Stage 1: `selection_image_1`

selection_image_1:
    Image|contains|all:
        - '\Windows\Installer\'
        - 'msi'
    Image|endswith: 'tmp'

Stage 2: `selection_image_2`

selection_image_2:
    Image|endswith: '\msiexec.exe'
    IntegrityLevel:
        - 'System'
        - 'S-1-16-16384'

Stage 3: `selection_user`

selection_user:
    User|contains:
        - 'AUTHORI'
        - 'AUTORI'

Stage 4: `not filter_*`

filter_installer:
    ParentImage: 'C:\Windows\System32\services.exe'
filter_repair:
    - CommandLine|endswith: '\system32\msiexec.exe /V'
    - ParentCommandLine|endswith: '\system32\msiexec.exe /V'
filter_sophos:
    ParentImage|startswith: 'C:\ProgramData\Sophos\'
filter_avira:
    ParentImage|startswith: 'C:\ProgramData\Avira\'
filter_avast:
    ParentImage|startswith:
        - 'C:\Program Files\Avast Software\'
        - 'C:\Program Files (x86)\Avast Software\'
filter_google_update:
    ParentImage|startswith:
        - 'C:\Program Files\Google\Update\'
        - 'C:\Program Files (x86)\Google\Update\'

Exclusions

Top-level NOT(...) conjuncts: predicates this rule actively suppresses.

Field	Kind	Excluded values
`CommandLine`	ends_with	`\system32\msiexec.exe /V`
`ParentCommandLine`	ends_with	`\system32\msiexec.exe /V`
`ParentImage`	eq	`C:\Windows\System32\services.exe`
`ParentImage`	starts_with	`C:\Program Files (x86)\Avast Software\`
`ParentImage`	starts_with	`C:\Program Files (x86)\Google\Update\`
`ParentImage`	starts_with	`C:\Program Files\Avast Software\`
`ParentImage`	starts_with	`C:\Program Files\Google\Update\`
`ParentImage`	starts_with	`C:\ProgramData\Avira\`
`ParentImage`	starts_with	`C:\ProgramData\Sophos\`

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
`Image`	ends_with	`\msiexec.exe` corpus 21 (sigma 21) `tmp`
`Image`	match	`\Windows\Installer\` `msi`
`IntegrityLevel`	eq	`S-1-16-16384` corpus 29 (sigma 22, splunk 4, elastic 3) `System` corpus 29 (sigma 22, splunk 4, elastic 3)
`User`	match	`AUTHORI` corpus 14 (sigma 14) `AUTORI` 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)

Always Install Elevated Windows Installer

MITRE ATT&CK coverage

Event coverage

Rule body yaml

Stages and Predicates

Stage 0: `condition`

Stage 1: `selection_image_1`

Stage 2: `selection_image_2`

Stage 3: `selection_user`

Stage 4: `not filter_*`

Exclusions

Indicators

Keyboard shortcuts

Search operators

Always Install Elevated Windows Installer

MITRE ATT&CK coverage

Event coverage

Rule body yaml

Stages and Predicates

Stage 0: condition

Stage 1: selection_image_1

Stage 2: selection_image_2

Stage 3: selection_user

Stage 4: not filter_*

Exclusions

Indicators

Stage 0: `condition`

Stage 1: `selection_image_1`

Stage 2: `selection_image_2`

Stage 3: `selection_user`

Stage 4: `not filter_*`