@dynatrace-oss/dynatrace-mcp-server has a DQL injection via parameters not documented as DQL

Summary

A DQL injection vulnerability in several read tools lets a caller bypass the tools' documented field-scope, time-window, and display caps by injecting DQL pipeline stages through parameters typed as identifiers.

Details

Several tools interpolate caller-supplied parameters directly into DQL query strings without quoting or escaping. The affected parameters are documented in their Zod schemas as identifiers or constrained shorthand (such as "24h" timeframe values or Kubernetes UIDs) - not as DQL expressions. The interpolation lets a caller break out of string literals, append arbitrary DQL pipeline stages, and use // line comments (documented in the Dynatrace DQL language reference) to discard the rest of the intended query.

The marginal-privilege ceiling is low because the operator's token also exposes execute_dql with full DQL access. What the injection grants is the ability to bypass the affected tools' contract: the readOnlyHint: true annotation that MCP clients may treat as a signal to auto-approve, the per-tool field selection (e.g., | fields id, name, type), the display caps (maxProblemsToDisplay, maxVulnerabilitiesToDisplay, maxEntitiesToDisplay), and the time-window bounds.

The vulnerable interpolations are:

All Zod schemas for these parameters use z.string() or z.array(z.string()) with no pattern validation.

PoC

clusterId - quote-and-comment break-out. With clusterId = 'x" or 1==1 //' the constructed query becomes:

| filter k8s.cluster.uid == "x" or 1==1 //" or dt.entity.kubernetes_cluster == ""

The first " closes the string literal, or 1==1 neutralises the filter to match every row, and // discards the rest of the line including the kubernetesEntityId guard.

entityNames - pipeline-stage injection. With entityNames = ['svc" | fields id, name, tags //'] the constructed smartscape query becomes:

smartscapeNodes "*" | search "*svc" | fields id, name, tags //*" | fields id, name, type

After the // line comment, the effective query is smartscapeNodes "*" | search "*svc" | fields id, name, tags. The original | fields id, name, type stage is suppressed and replaced with the attacker's field selection - the tool returns whatever field set the attacker requests (including ones not in the tool's documented output contract).

timeframe - prefix injection. With timeframe = '30d, to: now() | fieldsAdd internal_secret //' the list-problems query becomes:

fetch dt.davis.problems, from: now()-30d, to: now() | fieldsAdd internal_secret //, to: now()
| filter isNull(dt.davis.is_duplicate) OR not(dt.davis.is_duplicate)
...

A new pipeline stage is injected before the tool's intended | filter, and the rest of the query is commented out.

The server's own verify_dql tool can be used to confirm any specific injection payload parses as valid DQL.

Impact

• A caller (typically via prompt injection of an LLM that has access to the affected tools) can bypass the tools' field-scope, time-window, and display caps.
• The affected tools are annotated readOnlyHint: true, which some MCP clients treat as a signal to auto-approve. The injection turns a "safe" read tool into an arbitrary-DQL surface.
• No new data access beyond what execute_dql already provides - the marginal impact is the auto-approval pathway and the broken tool contract, not privilege escalation.