OSSEC Rootkit Detected via Osquery

Severity: medium
Log types: Osquery.Differential
Tags: Osquery, Malware, Defense Evasion:Rootkit
Reference: https://panther.com/blog/osquery-log-analysis/
Source: github.com/panther-labs/panther-analysis

Checks if any results are returned for the Osquery OSSEC Rootkit pack.

MITRE ATT&CK coverage

Tactic	Techniques
Stealth	`T1014` Rootkit

Rule body yaml

AnalysisType: rule
Filename: osquery_ossec.py
RuleID: "Osquery.OSSECRootkitDetected"
DisplayName: "OSSEC Rootkit Detected via Osquery"
Enabled: true
LogTypes:
  - Osquery.Differential
Tags:
  - Osquery
  - Malware
  - Defense Evasion:Rootkit
Reports:
  MITRE ATT&CK:
    - TA0005:T1014
Severity: Medium
Description: >
  Checks if any results are returned for the Osquery OSSEC Rootkit pack.
Runbook: >
  Verify the presence of the rootkit and re-image the machine.
Reference: https://panther.com/blog/osquery-log-analysis/
SummaryAttributes:
  - name
  - hostIdentifier
  - action
Tests:
  - Name: Rootkit Detected
    ExpectedResult: true
    Log:
      {
        "action": "added",
        "calendarTime": "Tue Sep 11 16:14:21 2018 UTC",
        "columns":
          {
            "build_distro": "10.12",
            "build_platform": "darwin",
            "config_hash": "1111",
            "config_valid": "1",
            "counter": "14",
            "global_state": "0",
            "extensions": "active",
            "instance_id": "1111",
            "pid": "223",
            "resident_size": "54894592",
            "start_time": "1536634519",
            "system_time": "12472",
            "user_time": "31800",
            "uuid": "37821E12-CC8A-5AA3-A90C-FAB28A5BF8F9",
            "version": "3.2.6",
            "watcher": "92",
          },
        "counter": "255",
        "decorations": { "host_uuid": "1111", "environment": "corp" },
        "epoch": "0",
        "hostIdentifier": "test.lan",
        "log_type": "result",
        "name": "pack_ossec-rootkit_pwned",
        "unixTime": "1536682461",
      }
  - Name: Rootkit Not Detected
    ExpectedResult: false
    Log:
      {
        "action": "added",
        "calendarTime": "Tue Sep 11 16:14:21 2018 UTC",
        "columns":
          {
            "build_distro": "10.12",
            "build_platform": "darwin",
            "config_hash": "1111",
            "config_valid": "1",
            "counter": "14",
            "global_state": "2",
            "extensions": "active",
            "instance_id": "1111",
            "pid": "223",
            "resident_size": "54894592",
            "start_time": "1536634519",
            "system_time": "12472",
            "user_time": "31800",
            "uuid": "37821E12-CC8A-5AA3-A90C-FAB28A5BF8F9",
            "version": "3.2.6",
            "watcher": "92",
          },
        "counter": "255",
        "decorations": { "host_uuid": "1111", "environment": "corp" },
        "epoch": "0",
        "hostIdentifier": "test.lan",
        "log_type": "result",
        "name": "pack_osquery-response_alf",
        "unixTime": "1536682461",
      }

Detection logic

Condition

name contains "ossec-rootkit"
action eq "added"

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
`action`	eq	`added` corpus 10 (panther 10)
`name`	contains	`ossec-rootkit`

Output fields

Fields the rule emits when it matches. Chronicle authors list these in the outcome block; they appear on the detection and $risk_score drives alerting. Sentinel / Defender XDR rules build them up through project / summarize / extend stages. Sentinel maps these into alert fields via entityMappings and customDetails; Defender XDR custom detections surface them as alert fields directly.

Field
`hostIdentifier`

`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)