Query-Language Pipeline Stage Smuggled Into an Identifier-Typed Tool Parameter

Detects a tool parameter that the tool's own schema describes as an IDENTIFIER -- entityName, entitySelector, table_name, index_name, metric_name, dashboard_id -- carrying a query-language pipeline stage instead: "host-1 | fetch logs | fields content | limit 50000". The observability backend concatenates the identifier into the query it builds, so the appended stages run with the server's credentials and outside every limit the tool documented -- different data source, different fields, a time window and row count the caller was never allowed to ask for. Mined from GHSA-pqh8-p93p-2rx7 (@dynatrace-oss/dynatrace-mcp-server), where parameters not documented as DQL were interpolated into DQL. The same shape appears wherever an MCP server builds a query language from "safe" fields: KQL's | externaldata, Splunk's | inputlookup, Lucene/ES pipelines. ATR-2026-00066 covers template and shell metacharacter injection in tool arguments and has no notion of a query-pipeline stage.

Response Actions

References

1. 01

   A JSON tool argument whose identifier-typed key carries a query pipeline stage. Unambiguous query verbs (externaldata, inputlookup, summarize, fieldsAdd, ...) stand alone; the three verbs that are also ordinary English words (fetch, fields, limit) additionally require a second pipe, a comparison or a function call, so a display label such as "Main Stage | Fetch Festival (2026)" does not qualify.

   field: contentop: regex

Attack Examples (Rule Triggers)

1. {"tool":"execute_dql","arguments":{"entityName":"host-1 | fetch logs | fields content | limit 50000"}}

2. {"entitySelector":"x\" | fetch security.events | fieldsAdd secret=lookup()"}

3. {"table_name":"orders | summarize count() by user_id"}

4. {"tool":"query_logs","arguments":{"index_name":"app-logs | externaldata (u:string) [@x.csv]"}}

Real-world attack payloads, sanitized and versioned alongside the rule as regression tests — so a future revision can't silently stop catching them.

Benign Examples (Rule Doesn't Trigger)

1. ADVERSARIAL: a real DQL query in the parameter that is documented as a query -- the pipeline belongs there

   {"query":"fetch logs | filter dt.entity.host == \"host-1\" | fields content | limit 100"}

2. Identifier and query supplied as separate parameters, which is the correct usage

   {"entityName":"host-1","query":"fetch logs | limit 100"}

3. A shell pipeline; head is not a query verb

   kubectl get pods -n prod -o name | head -20

4. A shell pipeline that happens to involve a cluster_name variable

   echo "$cluster_name" | tee -a cluster.log

5. Documentation showing a query, not assigned to an identifier field

   The DQL example in the docs is: fetch logs | fields timestamp, content | limit 20

6. ADVERSARIAL: an ordinary APL/Kusto query in which a quoted literal is followed by a pipe stage. This FIRED the first version of the rule on four real corpus samples and is why the free-standing string-break condition was deleted.

   ['logs'] | where service == "api" | summarize count() by bin_auto(_time)

7. ADVERSARIAL: the same ordinary query JSON-encoded, so the quote arrives escaped -- the shape that showed an escaped-quote condition could not stand on its own

   {"query":"AppEvents | where Level == \"Error\" | summarize count() by Source"}

8. A metric identifier holding a real metric key

   {"metric_name":"builtin:host.cpu.usage","resolution":"1m"}

9. Identifier holding a plain table name; the query verb appears only in a comment

   table_name = 'orders'  # summarize is done in the SELECT below

10. A dashboard identifier holding a UUID

    {"dashboard_id":"a1b2c3d4-5e6f-7890-abcd-ef1234567890"}

11. adversarial review 2026-08-24: nginx/Ansible upstream_name contains 'stream_name' as a substring

    {"upstream_name":"api | fetch-pool","weight":3}

12. adversarial review 2026-08-24: CMake/Bazel executable_name contains 'table_name' as a substring

    {"executable_name":"renderer | limit-rss","argv":["--headless"]}

13. adversarial review 2026-08-24: UI breadcrumb using the ubiquitous ' | ' title separator

    {"printable_name":"Orders | Fetch history"}

14. adversarial review 2026-08-24: allowlist regex whose second branch starts with a query verb

    stream_name = "^(orders|fetch)-events$"

15. adversarial review 2026-08-24: index pattern regex alternation

    index_name: "(app|fields)-2026.08"

16. adversarial review 2026-08-24: SECURITY WRITING EXPLAINING THIS EXACT ADVISORY

    GHSA-pqh8-p93p-2rx7: the server interpolated entityName: "host-1 | fetch logs | fields content" straight into the DQL it built.

17. adversarial review 2026-08-24: ATR's own rule documentation

    ATR-2026-02669 detects an identifier parameter such as table_name: "orders | summarize count()" carrying a pipeline stage.

18. adversarial review 2026-08-24: the MCP server's own regression test asserting rejection

    it('rejects smuggled stages', () => expect(() => run({entityName: "x | fetch logs"})).toThrow());

19. adversarial review 2026-08-24: changelog documenting the fix

    ## 1.4.2 Security\n- entitySelector = "x | fetch security.events" is now rejected instead of concatenated (GHSA-pqh8-p93p-2rx7).

20. adversarial review 2026-08-24: shell pipeline assigned to a cluster_name variable

    cluster_name="$(kubectl get ns | fields 1)"

21. adversarial review 2026-08-24: Traditional Chinese vulnerability explanation

    漏洞說明:當 table_name = "orders | summarize count()" 被直接串進查詢字串時,後端就會執行多餘的階段。

22. adversarial review 2026-08-24: live-stream display name using a ' | ' separator

    {"stream_name":"Main Stage | Fetch Festival 2026","bitrate":6000}

23. adversarial review 2026-08-24: live-stream title with a ' | ' separator and a parenthesised year

    {"stream_name":"Main Stage | Fetch Festival (2026)","bitrate":6000}

24. adversarial review 2026-08-24: team/entity display name

    {"entity_name":"EU West | Fetch & Ship (Ops)"}

25. adversarial review 2026-08-24: human-readable metric label

    {"metric_name":"Requests | Limit (p99)","unit":"ms"}

26. adversarial review 2026-08-24: cluster label noting a legacy naming scheme

    {"cluster_name":"prod | fields (legacy naming)"}

27. adversarial review 2026-08-24: index label mentioning a soft cap

    {"index_name":"app | limit (soft cap 5k)"}

28. adversarial review 2026-08-24: Traditional Chinese stream title

    {"stream_name":"主舞台 | Fetch 音樂節 (2026)"}

29. adversarial review 2026-08-24: table label documenting a deprecated alias

    {"table_name":"orders | fetch (deprecated alias)"}

Known False Positive Contexts

• ▸MEASURED AND FIXED 2026-08-24 (adversarial review, 19 benign probes through the shipped engine). The published version fired on 12 of 12 first-wave probes. Four separate defects, each fixed: (a) the identifier alternation had no leading boundary, so upstream_name, executable_name and printable_name matched by substring; (b) the value only needed a pipe somewhere, so allowlist regexes such as stream_name = "^(orders|fetch)-events$" and index_name: "(app|fields)-2026.08" fired; (c) the key could be unquoted and assigned with = or :, so ordinary prose fired -- a GHSA writeup, a CHANGELOG entry, a Traditional Chinese vulnerability explanation, the MCP server's own regression test asserting rejection, and ATR's own rule documentation; (d) a shell pipeline assigned to cluster_name fired.
• ▸MEASURED AND FIXED 2026-08-24, second wave. After (a)-(d) the rule still fired on 7 of 7 display labels that use the ubiquitous ' | ' title separator inside an identifier field: {"stream_name":"Main Stage | Fetch Festival (2026)"}, {"metric_name":"Requests | Limit (p99)"}, {"entity_name":"EU West | Fetch & Ship (Ops)"} and the Traditional Chinese equivalent. Fixed by splitting the verb list: externaldata / inputlookup / summarize / mv-expand / make-series / parse-kv / fieldsAdd / fieldsKeep / fieldsRemove are never ordinary English and stand alone, while fetch / fields / limit additionally require a second pipe, a comparison, or a function call in the following 24 characters.
• ▸A parameter documented as a query and legitimately containing a pipeline (a dql / query / kql field). Those field names are deliberately absent from the identifier list.
• ▸Shell pipelines in a command argument. The query verbs are not shell commands, and the value must be a quoted JSON string attached to an identifier key.
• ▸STATED GAP: the rule now requires the JSON object form ({"entityName":"..."}) that an mcp_exchange actually carries. A payload rendered as prose or as a Python kwarg (entityName: "x | fetch logs", index_name = '...') is no longer detected -- that form could not be separated from documentation describing the advisory, which is the single largest false-positive source for this rule.
• ▸STATED GAP: a pipeline written without a space after the pipe ("x|fetch logs") is not detected. The space is what separates a pipeline stage from a regex alternation such as (orders|fetch).

title: "Query-Language Pipeline Stage Smuggled Into an Identifier-Typed Tool Parameter"
id: ATR-2026-02669
rule_version: 1
status: experimental
description: >
  Detects a tool parameter that the tool's own schema describes as an
  IDENTIFIER -- entityName, entitySelector, table_name, index_name,
  metric_name, dashboard_id -- carrying a query-language pipeline stage
  instead: "host-1 | fetch logs | fields content | limit 50000".
  The observability backend concatenates the identifier into the query it
  builds, so the appended stages run with the server's credentials and outside
  every limit the tool documented -- different data source, different fields,
  a time window and row count the caller was never allowed to ask for.
  Mined from GHSA-pqh8-p93p-2rx7 (@dynatrace-oss/dynatrace-mcp-server), where
  parameters not documented as DQL were interpolated into DQL. The same shape
  appears wherever an MCP server builds a query language from "safe" fields:
  KQL's | externaldata, Splunk's | inputlookup, Lucene/ES pipelines.
  ATR-2026-00066 covers template and shell metacharacter injection in tool
  arguments and has no notion of a query-pipeline stage.
author: "ATR Community (GHSA sweep)"
date: "2026/08/23"
schema_version: "0.1"
detection_tier: pattern
maturity: test
severity: medium

references:
  ghsa:
    - "GHSA-pqh8-p93p-2rx7"
  cwe:
    - "CWE-943"
    - "CWE-88"
  owasp_llm:
    - "LLM06:2025"
  owasp_agentic:
    - "ASI05:2026"
  mitre_attack:
    - "T1213 - Data from Information Repositories"
  mitre_atlas:
    - "AML.T0053 - AI Agent Tool Invocation"
  external:
    - "https://github.com/advisories/GHSA-pqh8-p93p-2rx7"

metadata_provenance:
  ghsa: human-reviewed
  cwe: human-reviewed
  owasp_llm: human-reviewed
  owasp_agentic: human-reviewed
  mitre_attack: human-reviewed
  mitre_atlas: human-reviewed

compliance:
  eu_ai_act:
    - article: "15"
      context: "Article 15 (accuracy, robustness and cybersecurity) requires resistance to input that alters system behaviour; a pipeline stage inside an identifier field rewrites the query the server executes."
      strength: primary
    - article: "10"
      context: "Article 10 (data and data governance): the appended stages read data sets the tool never declared, which is a data-governance boundary failure."
      strength: secondary
  nist_ai_rmf:
    - subcategory: "MG.2.3"
      context: "Query-language injection through agent tool parameters is an identified AI risk; this rule is the runtime countermeasure."
      strength: primary
    - subcategory: "MP.5.1"
      context: "Recording observability-query injection in the organizational AI risk register."
      strength: secondary
  iso_42001:
    - clause: "8.1"
      context: "ISO/IEC 42001 Clause 8.1 (operational planning and control): the documented parameter contract is an operational control, and this rule reports values that break it."
      strength: primary
    - clause: "8.3"
      context: "ISO/IEC 42001 Clause 8.3 (AI risk treatment) is implemented by alerting before the concatenated query is executed."
      strength: secondary

tags:
  category: tool-poisoning
  subcategory: query-language-injection
  scan_target: runtime
  confidence: high

agent_source:
  type: mcp_exchange
  framework:
    - any
  provider:
    - any

detection:
  condition: any
  conditions:
    - field: content
      operator: regex
      value: '[{,]\s{0,3}"(?:entity_?name|entity_?selector|table_?name|index_?name|metric_?name|dashboard_?id|cluster_?name|stream_?name)"\s{0,3}:\s{0,3}"(?:[^"\\\n,:]|\\.){0,40}\|\s{1,3}(?:(?:externaldata|inputlookup|mv-expand|make-series|parse-kv|fieldsadd|fieldskeep|fieldsremove|summarize)\b|(?:fetch|fields|limit)\b[^\r\n]{0,24}(?:\||==|\w\())'
      description: "A JSON tool argument whose identifier-typed key carries a query pipeline stage. Unambiguous query verbs (externaldata, inputlookup, summarize, fieldsAdd, ...) stand alone; the three verbs that are also ordinary English words (fetch, fields, limit) additionally require a second pipe, a comparison or a function call, so a display label such as \"Main Stage | Fetch Festival (2026)\" does not qualify."
  false_positives:
    - "MEASURED AND FIXED 2026-08-24 (adversarial review, 19 benign probes through the shipped engine). The published version fired on 12 of 12 first-wave probes. Four separate defects, each fixed: (a) the identifier alternation had no leading boundary, so upstream_name, executable_name and printable_name matched by substring; (b) the value only needed a pipe somewhere, so allowlist regexes such as stream_name = \"^(orders|fetch)-events$\" and index_name: \"(app|fields)-2026.08\" fired; (c) the key could be unquoted and assigned with = or :, so ordinary prose fired -- a GHSA writeup, a CHANGELOG entry, a Traditional Chinese vulnerability explanation, the MCP server's own regression test asserting rejection, and ATR's own rule documentation; (d) a shell pipeline assigned to cluster_name fired."
    - "MEASURED AND FIXED 2026-08-24, second wave. After (a)-(d) the rule still fired on 7 of 7 display labels that use the ubiquitous ' | ' title separator inside an identifier field: {\"stream_name\":\"Main Stage | Fetch Festival (2026)\"}, {\"metric_name\":\"Requests | Limit (p99)\"}, {\"entity_name\":\"EU West | Fetch & Ship (Ops)\"} and the Traditional Chinese equivalent. Fixed by splitting the verb list: externaldata / inputlookup / summarize / mv-expand / make-series / parse-kv / fieldsAdd / fieldsKeep / fieldsRemove are never ordinary English and stand alone, while fetch / fields / limit additionally require a second pipe, a comparison, or a function call in the following 24 characters."
    - "A parameter documented as a query and legitimately containing a pipeline (a dql / query / kql field). Those field names are deliberately absent from the identifier list."
    - "Shell pipelines in a command argument. The query verbs are not shell commands, and the value must be a quoted JSON string attached to an identifier key."
    - "STATED GAP: the rule now requires the JSON object form ({\"entityName\":\"...\"}) that an mcp_exchange actually carries. A payload rendered as prose or as a Python kwarg (entityName: \"x | fetch logs\", index_name = '...') is no longer detected -- that form could not be separated from documentation describing the advisory, which is the single largest false-positive source for this rule."
    - "STATED GAP: a pipeline written without a space after the pipe (\"x|fetch logs\") is not detected. The space is what separates a pipeline stage from a regex alternation such as (orders|fetch)."

response:
  actions:
    - alert
  message_template: >
    [ATR-2026-02669] An identifier-typed tool parameter carries a query
    pipeline stage. The backend will concatenate it into the query it builds --
    reject the value or bind it as a parameter instead of concatenating.

confidence: 78

test_cases:
  true_positives:
    - input: '{"tool":"execute_dql","arguments":{"entityName":"host-1 | fetch logs | fields content | limit 50000"}}'
      expected: triggered
      description: "GHSA-pqh8-p93p-2rx7 -- entityName carrying extra DQL stages, in the JSON form it takes on an mcp_exchange"
    - input: '{"entitySelector":"x\" | fetch security.events | fieldsAdd secret=lookup()"}'
      expected: triggered
      description: "String-break form: the quote is closed and a new stage appended"
    - input: '{"table_name":"orders | summarize count() by user_id"}'
      expected: triggered
      description: "KQL summarize appended to a table identifier"
    - input: '{"tool":"query_logs","arguments":{"index_name":"app-logs | externaldata (u:string) [@x.csv]"}}'
      expected: triggered
      description: "KQL externaldata pulling a remote file through an index identifier"
  true_negatives:
    - input: '{"query":"fetch logs | filter dt.entity.host == \"host-1\" | fields content | limit 100"}'
      expected: not_triggered
      description: "ADVERSARIAL: a real DQL query in the parameter that is documented as a query -- the pipeline belongs there"
    - input: '{"entityName":"host-1","query":"fetch logs | limit 100"}'
      expected: not_triggered
      description: "Identifier and query supplied as separate parameters, which is the correct usage"
    - input: 'kubectl get pods -n prod -o name | head -20'
      expected: not_triggered
      description: "A shell pipeline; head is not a query verb"
    - input: 'echo "$cluster_name" | tee -a cluster.log'
      expected: not_triggered
      description: "A shell pipeline that happens to involve a cluster_name variable"
    - input: 'The DQL example in the docs is: fetch logs | fields timestamp, content | limit 20'
      expected: not_triggered
      description: "Documentation showing a query, not assigned to an identifier field"
    - input: "['logs'] | where service == \"api\" | summarize count() by bin_auto(_time)"
      expected: not_triggered
      description: "ADVERSARIAL: an ordinary APL/Kusto query in which a quoted literal is followed by a pipe stage. This FIRED the first version of the rule on four real corpus samples and is why the free-standing string-break condition was deleted."
    - input: '{"query":"AppEvents | where Level == \"Error\" | summarize count() by Source"}'
      expected: not_triggered
      description: "ADVERSARIAL: the same ordinary query JSON-encoded, so the quote arrives escaped -- the shape that showed an escaped-quote condition could not stand on its own"
    - input: '{"metric_name":"builtin:host.cpu.usage","resolution":"1m"}'
      expected: not_triggered
      description: "A metric identifier holding a real metric key"
    - input: "table_name = 'orders'  # summarize is done in the SELECT below"
      expected: not_triggered
      description: "Identifier holding a plain table name; the query verb appears only in a comment"
    - input: '{"dashboard_id":"a1b2c3d4-5e6f-7890-abcd-ef1234567890"}'
      expected: not_triggered
      description: "A dashboard identifier holding a UUID"
    - input: '{"upstream_name":"api | fetch-pool","weight":3}'
      expected: not_triggered
      description: 'adversarial review 2026-08-24: nginx/Ansible upstream_name contains ''stream_name'' as a substring'
    - input: '{"executable_name":"renderer | limit-rss","argv":["--headless"]}'
      expected: not_triggered
      description: 'adversarial review 2026-08-24: CMake/Bazel executable_name contains ''table_name'' as a substring'
    - input: '{"printable_name":"Orders | Fetch history"}'
      expected: not_triggered
      description: 'adversarial review 2026-08-24: UI breadcrumb using the ubiquitous '' | '' title separator'
    - input: 'stream_name = "^(orders|fetch)-events$"'
      expected: not_triggered
      description: 'adversarial review 2026-08-24: allowlist regex whose second branch starts with a query verb'
    - input: 'index_name: "(app|fields)-2026.08"'
      expected: not_triggered
      description: 'adversarial review 2026-08-24: index pattern regex alternation'
    - input: 'GHSA-pqh8-p93p-2rx7: the server interpolated entityName: "host-1 | fetch logs | fields content" straight into the DQL it built.'
      expected: not_triggered
      description: 'adversarial review 2026-08-24: SECURITY WRITING EXPLAINING THIS EXACT ADVISORY'
    - input: 'ATR-2026-02669 detects an identifier parameter such as table_name: "orders | summarize count()" carrying a pipeline stage.'
      expected: not_triggered
      description: 'adversarial review 2026-08-24: ATR''s own rule documentation'
    - input: 'it(''rejects smuggled stages'', () => expect(() => run({entityName: "x | fetch logs"})).toThrow());'
      expected: not_triggered
      description: 'adversarial review 2026-08-24: the MCP server''s own regression test asserting rejection'
    - input: '## 1.4.2 Security\n- entitySelector = "x | fetch security.events" is now rejected instead of concatenated (GHSA-pqh8-p93p-2rx7).'
      expected: not_triggered
      description: 'adversarial review 2026-08-24: changelog documenting the fix'
    - input: 'cluster_name="$(kubectl get ns | fields 1)"'
      expected: not_triggered
      description: 'adversarial review 2026-08-24: shell pipeline assigned to a cluster_name variable'
    - input: '漏洞說明:當 table_name = "orders | summarize count()" 被直接串進查詢字串時,後端就會執行多餘的階段。'
      expected: not_triggered
      description: 'adversarial review 2026-08-24: Traditional Chinese vulnerability explanation'
    - input: '{"stream_name":"Main Stage | Fetch Festival 2026","bitrate":6000}'
      expected: not_triggered
      description: 'adversarial review 2026-08-24: live-stream display name using a '' | '' separator'
    - input: '{"stream_name":"Main Stage | Fetch Festival (2026)","bitrate":6000}'
      expected: not_triggered
      description: 'adversarial review 2026-08-24: live-stream title with a '' | '' separator and a parenthesised year'
    - input: '{"entity_name":"EU West | Fetch & Ship (Ops)"}'
      expected: not_triggered
      description: 'adversarial review 2026-08-24: team/entity display name'
    - input: '{"metric_name":"Requests | Limit (p99)","unit":"ms"}'
      expected: not_triggered
      description: 'adversarial review 2026-08-24: human-readable metric label'
    - input: '{"cluster_name":"prod | fields (legacy naming)"}'
      expected: not_triggered
      description: 'adversarial review 2026-08-24: cluster label noting a legacy naming scheme'
    - input: '{"index_name":"app | limit (soft cap 5k)"}'
      expected: not_triggered
      description: 'adversarial review 2026-08-24: index label mentioning a soft cap'
    - input: '{"stream_name":"主舞台 | Fetch 音樂節 (2026)"}'
      expected: not_triggered
      description: 'adversarial review 2026-08-24: Traditional Chinese stream title'
    - input: '{"table_name":"orders | fetch (deprecated alias)"}'
      expected: not_triggered
      description: 'adversarial review 2026-08-24: table label documenting a deprecated alias'