Hack Tool User Agent

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

Detects suspicious user agent strings user by hack tools in proxy logs

MITRE ATT&CK coverage

Tactic	Techniques
Initial Access	`T1190` Exploit Public-Facing Application
Credential Access	`T1110` Brute Force

Rule body yaml

title: Hack Tool User Agent
id: c42a3073-30fb-48ae-8c99-c23ada84b103
status: test
description: Detects suspicious user agent strings user by hack tools in proxy logs
references:
    - https://github.com/fastly/waf_testbed/blob/8bfc406551f3045e418cbaad7596cff8da331dfc/templates/default/scanners-user-agents.data.erb
    - http://rules.emergingthreats.net/open/snort-2.9.0/rules/emerging-user_agents.rules
author: Florian Roth (Nextron Systems)
date: 2017-07-08
modified: 2022-07-07
tags:
    - attack.initial-access
    - attack.t1190
    - attack.credential-access
    - attack.t1110
logsource:
    category: proxy
detection:
    selection:
        c-useragent|contains:
            # Vulnerability scanner and brute force tools
            - '(hydra)'
            - ' arachni/'
            - ' BFAC '
            - ' brutus '
            - ' cgichk '
            - 'core-project/1.0'
            - ' crimscanner/'
            - 'datacha0s'
            - 'dirbuster'
            - 'domino hunter'
            - 'dotdotpwn'
            - 'FHScan Core'
            - 'floodgate'
            - 'get-minimal'
            - 'gootkit auto-rooter scanner'
            - 'grendel-scan'
            - ' inspath '
            - 'internet ninja'
            - 'jaascois'
            - ' zmeu '
            - 'masscan'
            - ' metis '
            - 'morfeus fucking scanner'
            - 'n-stealth'
            - 'nsauditor'
            - 'pmafind'
            - 'security scan'
            - 'springenwerk'
            - 'teh forest lobster'
            - 'toata dragostea'
            - ' vega/'
            - 'voideye'
            - 'webshag'
            - 'webvulnscan'
            - ' whcc/'
            # SQL Injection
            - ' Havij'
            - 'absinthe'
            - 'bsqlbf'
            - 'mysqloit'
            - 'pangolin'
            - 'sql power injector'
            - 'sqlmap'
            - 'sqlninja'
            - 'uil2pn'
            # Hack tool
            - 'ruler'  # https://www.crowdstrike.com/blog/using-outlook-forms-lateral-movement-persistence/
            - 'Mozilla/5.0 (Windows; U; Windows NT 5.1; pt-PT; rv:1.9.1.2) Gecko/20090729 Firefox/3.5.2 (.NET CLR 3.5.30729)'  # SQLi Dumper
    condition: selection
falsepositives:
    - Unknown
level: high

Stages and Predicates

Stage 0: `condition`

selection

Stage 1: `selection`

selection:
    c-useragent|contains:
        - '(hydra)'
        - ' arachni/'
        - ' BFAC '
        - ' brutus '
        - ' cgichk '
        - 'core-project/1.0'
        - ' crimscanner/'
        - 'datacha0s'
        - 'dirbuster'
        - 'domino hunter'
        - 'dotdotpwn'
        - 'FHScan Core'
        - 'floodgate'
        - 'get-minimal'
        - 'gootkit auto-rooter scanner'
        - 'grendel-scan'
        - ' inspath '
        - 'internet ninja'
        - 'jaascois'
        - ' zmeu '
        - 'masscan'
        - ' metis '
        - 'morfeus fucking scanner'
        - 'n-stealth'
        - 'nsauditor'
        - 'pmafind'
        - 'security scan'
        - 'springenwerk'
        - 'teh forest lobster'
        - 'toata dragostea'
        - ' vega/'
        - 'voideye'
        - 'webshag'
        - 'webvulnscan'
        - ' whcc/'
        - ' Havij'
        - 'absinthe'
        - 'bsqlbf'
        - 'mysqloit'
        - 'pangolin'
        - 'sql power injector'
        - 'sqlmap'
        - 'sqlninja'
        - 'uil2pn'
        - 'ruler'
        - 'Mozilla/5.0 (Windows; U; Windows NT 5.1; pt-PT; rv:1.9.1.2) Gecko/20090729 Firefox/3.5.2 (.NET CLR 3.5.30729)'

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
`c-useragent`	match	`BFAC` `Havij` `arachni/` `brutus` `cgichk` `crimscanner/` `inspath` `metis` `vega/` `whcc/` `zmeu` `(hydra)` `FHScan Core` `Mozilla/5.0 (Windows; U; Windows NT 5.1; pt-PT; rv:1.9.1.2) Gecko/20090729 Firefox/3.5.2 (.NET CLR 3.5.30729)` `absinthe` `bsqlbf` `core-project/1.0` `datacha0s` `dirbuster` `domino hunter` `dotdotpwn` `floodgate` `get-minimal` `gootkit auto-rooter scanner` `grendel-scan` `internet ninja` `jaascois` `masscan` `morfeus fucking scanner` `mysqloit` `n-stealth` `nsauditor` `pangolin` `pmafind` `ruler` `security scan` `springenwerk` `sql power injector` `sqlmap` `sqlninja` `teh forest lobster` `toata dragostea` `uil2pn` `voideye` `webshag` `webvulnscan`

`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)

Hack Tool User Agent

MITRE ATT&CK coverage

Rule body yaml

Stages and Predicates

Stage 0: `condition`

Stage 1: `selection`

Indicators

Keyboard shortcuts

Search operators

Hack Tool User Agent

MITRE ATT&CK coverage

Rule body yaml

Stages and Predicates

Stage 0: condition

Stage 1: selection

Indicators

Stage 0: `condition`

Stage 1: `selection`