Antivirus Relevant File Paths Alerts

Status: test
Severity: high
Log source: category antivirus
Author: Florian Roth (Nextron Systems), Arnim Rupp
Source: github.com/SigmaHQ/sigma

Detects an Antivirus alert in a highly relevant file path or with a relevant file name. This event must not be ignored just because the AV has blocked the malware but investigate, how it came there in the first place.

MITRE ATT&CK coverage

Tactic	Techniques
Resource Development	`T1588` Obtain Capabilities

Rule body yaml

title: Antivirus Relevant File Paths Alerts
id: c9a88268-0047-4824-ba6e-4d81ce0b907c
status: test
description: |
    Detects an Antivirus alert in a highly relevant file path or with a relevant file name.
    This event must not be ignored just because the AV has blocked the malware but investigate, how it came there in the first place.
references:
    - https://www.nextron-systems.com/?s=antivirus
author: Florian Roth (Nextron Systems), Arnim Rupp
date: 2018-09-09
modified: 2024-11-02
tags:
    - attack.resource-development
    - attack.t1588
logsource:
    category: antivirus
detection:
    selection_path:
        Filename|contains:
            - ':\PerfLogs\'
            - ':\Temp\'
            - ':\Users\Default\'
            - ':\Users\Public\'
            - ':\Windows\'
            - '/www/'
            # - '\Client\'
            - '\inetpub\'
            - '\tsclient\'
            - 'apache'
            - 'nginx'
            - 'tomcat'
            - 'weblogic'
    selection_ext:
        Filename|endswith:
            - '.asax'
            - '.ashx'
            - '.asmx'
            - '.asp'
            - '.aspx'
            - '.bat'
            - '.cfm'
            - '.cgi'
            - '.chm'
            - '.cmd'
            - '.dat'
            - '.ear'
            - '.gif'
            - '.hta'
            - '.jpeg'
            - '.jpg'
            - '.jsp'
            - '.jspx'
            - '.lnk'
            - '.msc'
            - '.php'
            - '.pl'
            - '.png'
            - '.ps1'
            - '.psm1'
            - '.py'
            - '.pyc'
            - '.rb'
            - '.scf'
            - '.sct'
            - '.sh'
            - '.svg'
            - '.txt'
            - '.vbe'
            - '.vbs'
            - '.war'
            - '.wll'
            - '.wsf'
            - '.wsh'
            - '.xll'
            - '.xml'
    condition: 1 of selection_*
falsepositives:
    - Unlikely
level: high

Stages and Predicates

Stage 0: `condition`

1 of selection_*

Stage 1: `selection_path`

selection_path:
    Filename|contains:
        - ':\PerfLogs\'
        - ':\Temp\'
        - ':\Users\Default\'
        - ':\Users\Public\'
        - ':\Windows\'
        - '/www/'
        - '\inetpub\'
        - '\tsclient\'
        - 'apache'
        - 'nginx'
        - 'tomcat'
        - 'weblogic'

Stage 2: `selection_ext`

selection_ext:
    Filename|endswith:
        - '.asax'
        - '.ashx'
        - '.asmx'
        - '.asp'
        - '.aspx'
        - '.bat'
        - '.cfm'
        - '.cgi'
        - '.chm'
        - '.cmd'
        - '.dat'
        - '.ear'
        - '.gif'
        - '.hta'
        - '.jpeg'
        - '.jpg'
        - '.jsp'
        - '.jspx'
        - '.lnk'
        - '.msc'
        - '.php'
        - '.pl'
        - '.png'
        - '.ps1'
        - '.psm1'
        - '.py'
        - '.pyc'
        - '.rb'
        - '.scf'
        - '.sct'
        - '.sh'
        - '.svg'
        - '.txt'
        - '.vbe'
        - '.vbs'
        - '.war'
        - '.wll'
        - '.wsf'
        - '.wsh'
        - '.xll'
        - '.xml'

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
`Filename`	ends_with	`.asax` `.ashx` `.asmx` `.asp` `.aspx` `.bat` `.cfm` `.cgi` `.chm` `.cmd` `.dat` `.ear` `.gif` `.hta` `.jpeg` `.jpg` `.jsp` `.jspx` `.lnk` `.msc` `.php` `.pl` `.png` `.ps1` `.psm1` `.py` `.pyc` `.rb` `.scf` `.sct` `.sh` `.svg` `.txt` `.vbe` `.vbs` `.war` `.wll` `.wsf` `.wsh` `.xll` `.xml`
`Filename`	match	`/www/` `:\PerfLogs\` `:\Temp\` `:\Users\Default\` `:\Users\Public\` `:\Windows\` `\inetpub\` `\tsclient\` `apache` `nginx` `tomcat` `weblogic`

`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)

Antivirus Relevant File Paths Alerts

MITRE ATT&CK coverage

Rule body yaml

Stages and Predicates

Stage 0: `condition`

Stage 1: `selection_path`

Stage 2: `selection_ext`

Indicators

Keyboard shortcuts

Search operators

Antivirus Relevant File Paths Alerts

MITRE ATT&CK coverage

Rule body yaml

Stages and Predicates

Stage 0: condition

Stage 1: selection_path

Stage 2: selection_ext

Indicators

Stage 0: `condition`

Stage 1: `selection_path`

Stage 2: `selection_ext`