Does one authorized request change reproducibly alter an HTTP outcome?
MRMA answers that question with repeated controls, bounded mutations, and independently verifiable evidence.

Current release: v0.4.5. MRMA uses semantic HTTP through HTTPX. It does not claim wire-exact replay, prove exploitability, assign severity, or identify a proprietary component from black-box behavior.

Why MRMA exists

Security testing often observes that a request changed and a response changed. That alone does not establish influence. Dynamic content, connection state, retries, redirects, and unstable controls can produce the same appearance.

MRMA treats the task as a controlled experiment:

1. Predeclare a baseline, one mutation, policies, bounds, and a fixed sample.
2. Bracket mutations with controls or use a seeded balanced schedule.
3. Reject unstable, incomplete, unauthorized, or resource-limited evidence.
4. Return a narrow conclusion with the observations, limitations, and provenance needed to check it.

Enforcement pipeline

No HTTP attempt can bypass the shared runtime sequence.

Authorization decision
        |
        v
Final HTTPX request preparation
        |
        v
Budget reservation
        |
        v
Immediate authorization revalidation
        |
        v
Journaled attempt identity
        |
        v
Semantic HTTP send
        |
        v
Budget commit + bounded observation
        |
        v
Comparison + fixed-sample conclusion

Boundary	Enforced behavior
Authorization	Exact ASCII host labels, target representation, CIDR, method, operation kind, path, query, authority, proxy, redirect, mutation, and expiry policy
Effective authority	URL, Host, TLS SNI, and proxy CONNECT are checked separately; duplicate Host fields are rejected
Redirects	Every hop is manually resolved, reauthorized, budgeted, and journaled
Cross-origin state	Caller fields are deny-by-default; the final HTTPX-built request also suppresses cookie-jar and explicit Cookie fields unless policy explicitly allows them
Budgets	The final prepared request and bounded response representation, including fields added by HTTPX, use one reserve/commit ledger with attempts, roles, redirects, retries, targets, origins, duration, depth, concurrency, and method risk
Evidence	Effective plan digest, result, journal, schema, benchmark, runtime data, and bundle file digests are cross-checked offline

Install

python -m pip install mrma==0.4.5
mrma --version

MRMA is tested on Python 3.10 and 3.13 across Linux, Windows, and macOS.

The published container supports Linux AMD64 and ARM64:

docker pull ghcr.io/0xmrma/mrma:0.4.5
docker run --rm ghcr.io/0xmrma/mrma:0.4.5 --version

Start without network traffic

Run the packaged 22-case loopback corpus:

mrma benchmark --out-json benchmark.json

Validate the example authorization policy:

mrma authorization validate examples/authorization.local.json --json

Inspect the maximum experiment plan without sending a request:

mrma experiment \
  --url http://127.0.0.1:8000/ \
  --set-header "X-Probe: 1" \
  --assurance research \
  --authorization examples/authorization.local.json \
  --journal local-plan.journal.jsonl \
  --dry-run

Dry-run output includes a local deterministic approval-plan digest. The privacy-safe plan digest in shared evidence remains run-local and intentionally cannot correlate private request values across runs.

The example policy authorizes loopback only. Start a service on 127.0.0.1:8000, then execute the same plan and produce a deterministic evidence bundle:

mrma experiment \
  --url http://127.0.0.1:8000/ \
  --set-header "X-Probe: 1" \
  --assurance research \
  --authorization examples/authorization.local.json \
  --journal local-run.journal.jsonl \
  --bundle local-run.zip \
  --json > local-run.json

mrma evidence verify local-run.zip --json

Authorization manifests are policy inputs, not proof of permission. Use a short-lived manifest issued under the target owner's actual approval process.

Result semantics

Conclusion	Meaning
INFLUENCE_DETECTED	Controls were stable and the 95% lower bound for changed mutation pairs met the predeclared reproducibility threshold
NO_INFLUENCE_OBSERVED	Controls were stable and the 95% upper bound stayed below the predeclared no-influence threshold
INCONCLUSIVE	Sampling, controls, authorization, transport, policy, body evidence, or comparator resources did not support either conclusion

These are experiment conclusions, not vulnerability or safety labels. Automation exit codes are opt-in: 10 for influence and 11 for inconclusive under the selected --fail-on policy.

Evidence bundle

evidence.zip
|-- manifest.json       file set, sizes, and SHA-256 digests
|-- result.json         strict mrma.experiment/v9 document
|-- plan.json           privacy-safe effective plan + bound digest
|-- journal.jsonl       append-only hash-chained runtime events
|-- authorization.json  non-executable policy summary
|-- benchmark.json      packaged release baseline
|-- runtime.json        tool and dependency provenance
|-- schema.json         exact result schema
`-- REPLAY.md           offline verification instructions

mrma evidence verify checks the bundle manifest, exact schema, result cross-fields, effective-plan digest, RUN_PLANNED linkage, journal chain/head/count, observation topology, authorization summary, benchmark contract, aggregate statistics, confidence intervals, and final verdict. Integrity verification does not prove who created an entirely new bundle; artifact authenticity is supplied separately by GitHub release and OCI attestations.

Workflows

Interface	Role	Output
experiment	Confirmatory fixed-sample oracle	Strict v9 result and optional evidence bundle
impact	Exploratory candidate ranking	Candidate manifest for independent confirmation
run, diff, discover, isolate, profiles, report	Policy-guarded exploration	Bounded observations and journal events
benchmark	Deterministic local validation	Schema-validated 22-case result
authorization validate	Offline policy validation	Canonical policy summary and digest
evidence verify	Offline integrity verification	Typed verification result or integrity error

All exploratory sends retain the immutable workflow baseline and apply the same header-mutation policy before networking. Exploratory output is not promoted to confirmatory evidence.

Design boundaries

• Semantic HTTP only. HTTPX may normalize request syntax; no wire-byte equivalence is claimed.
• Response bodies are bounded. Truncation or comparator exhaustion becomes structured uncertainty.
• Default comparison does not mask identifier-shaped values. Explicit normalization can support a changed result, but cannot turn different complete body digests into a no-influence result.
• Standard and strict privacy use run-local HMAC fingerprints, while selected policy and journal identifiers remain deterministically linkable and are declared as such.
• The hash chain detects modification of an existing journal. It is not an author signature.
• Authorization v1 remains readable; new policies should use strict mrma.authorization/v2.
• Published schema versions remain packaged and byte-locked for compatibility.

Documentation

Topic	Document
Runtime structure	Architecture
Policy contract	Authorization
Request accounting	Budget model
Result and bundle integrity	Evidence model
Fixed-sample decisions	Statistical model
HTTP comparison rules	HTTP semantics
Security assumptions	Threat model
Reproducible corpus	Benchmark
Typed interfaces	Python API
Verification record	Validation
Artifact provenance	Release verification

Release integrity

Releases use protected, SSH-signed annotated tags. GitHub Actions builds the wheel, source archive, and multi-platform OCI index, then publishes provenance attestations and an SBOM. Verification commands and trust boundaries are documented in Release verification.

Responsible use

Use MRMA only against targets and request effects explicitly authorized by the target owner. Keep methods, paths, redirect destinations, CIDRs, mutation names, rates, bytes, and expiry narrower than the experiment requires. Report defects through GitHub's private Security Advisory flow described in SECURITY.md.

Author and license

Created by Mohamed Abdelaal / 0xMRMA. Released under the MIT License.