go-authcrunch threat-hunting workflow for security audits, vulnerability triage, and deep review of authentication and authorization boundaries. Use when auditing the package for security issues, validating external vulnerability reports, reviewing authn/authz bypasses, ACL/path matching, redirects, token/cookie/session handling, OAuth/SAML/LDAP/KMS flows, input parsing, concurrency, secret logging, dependency vulnerabilities, or producing security findings and remediation plans.
Installation
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go-authcrunch threat-hunting workflow for security audits, vulnerability triage, and deep review of authentication and authorization boundaries. Use when auditing the package for security issues, validating external vulnerability reports, reviewing authn/authz bypasses, ACL/path matching, redirects, token/cookie/session handling, OAuth/SAML/LDAP/KMS flows, input parsing, concurrency, secret logging, dependency vulnerabilities, or producing security findings and remediation plans.
Threat Hunting
Operating Posture
Treat every authentication shortcut, authorization shortcut, redirect, token
source, cookie, forwarded header, parser, cache, and cryptographic decision as a
security boundary until proven otherwise.
Skepticism is a verification mode, not a reason to dismiss a report. Translate
claims into falsifiable checks, then test or inspect the exact runtime behavior.
Core authorization question — answer it for every protected path:
What object is being authorized?
What object is later served, proxied, redirected to, or trusted?
Are those objects represented by the same normalized value?
Which checks execute before token validation, ACL evaluation, or signature
verification?
Use the repo-local coding-directives skill for fixes, testing-and-ci for
test selection, and scripts-and-automation for repository tooling.
For external vulnerability reports, extract before judging:
Entry point and exact package/function names
Required configuration and deployment assumptions
Claimed payloads and their expected parsed forms
The check that should have run but did not
Downstream sink or side effect
Severity claim and whether it depends on a separate component
If a report is plausible but deployment-dependent, classify it that way and
still consider a library hardening fix when the package makes an unsafe
normalization, trust, or ordering assumption.
2. Map the Decision Path
Follow the call chain from input → decision → sink. Do not stop at a grep hit.
Document any tool that requires network access, an updated vulnerability
database, or loopback listeners; record that condition in validation notes.
Treat govulncheck findings in the Go standard library as release/toolchain
notes unless this repository is the final binary being shipped. For this
library, do not report stdlib CVEs as library-code findings or recommend
raising the go directive solely to clear them. Document the scanning
toolchain, the downstream/final binary build toolchain, and whether consumers
need a patched Go release on their supported Go line.
4. Hunt URL and Path Canonicalization
For any path-based auth, bypass, ACL, route, redirect, or upstream decision,
verify the exact representation used at the moment of the security check.
Check for:
Matching on r.URL.Path, r.RequestURI, r.URL.String(), or raw config
before normalization
Prefix/partial/suffix/regex comparisons on unnormalized values
Different normalization between the auth layer and the upstream/backend
filepath.Clean used for URL paths instead of path.Clean
Loss of meaningful trailing slash semantics after cleaning
Prefix rules that unintentionally match sibling paths (e.g., /public →
/publicity)
Scheme-relative redirect targets beginning with //
Query-string tokens or redirect parameters leaking into logs or Location
Encoded slash, encoded dot segment, duplicate slash, and absolute-form inputs
For each payload, verify the parsed value and the security decision. In Go
tests, assert or log req.URL.Path, req.URL.RawPath, req.RequestURI, and
the result of any normalization helper used by the production code.
5. Hunt Redirect and Header Trust Issues
Review every Location header, HTML/JS redirect, return URL, logout URL,
callback URL, and "current URL" helper.
Check for:
Raw insertion of r.URL.String(), RequestURI, Host, or X-Forwarded-*
into Location
Absolute or scheme-relative attacker-controlled redirect targets
Missing allowlist check on redirect destination
Full current-URL construction that trusts forwarded headers outside the
embedding solution's documented header-normalization boundary
Query parameter interpolation without url.QueryEscape
Response splitting or invalid header characters
Post-logout redirect to attacker-controlled URL
Referer-based redirect without validation
When a placeholder intentionally expands to an absolute URL, document the trust
model and the headers or config that define the allowed host set.
Do not report "Source-Address Authorization Trusts Forwarded IP Headers" as
a go-authcrunch library finding. AuthCrunch consumes the request metadata
provided by the embedding application or server. Protection, stripping, and
normalization of X-Forwarded-*, X-Real-IP, and similar client-IP headers is
the responsibility of the solution using this library. Document that deployment
assumption when relevant, but do not recommend implementing trusted-proxy
enforcement in this library unless go-authcrunch itself becomes the final
network edge for the affected flow.
6. Hunt Token, Cookie, and Session Issues
Token sources and propagation:
Default acceptance of query-string tokens (leaks to logs, referrers, proxies)
Tokens left in upstream headers, cookies, query strings, redirects, or logs
Multiple token sources with ambiguous or undefined precedence
Bearer/header validation that fails open when API-key or basic auth paths err
Cached users bypassing newer ACL, path, source-address, or token checks
JWT algorithm confusion: RS256 public key accepted as HS256 HMAC secret
alg: none acceptance or missing algorithm allowlist
Missing kid validation allowing key-set confusion
Treat debug-level OAuth/OIDC token, code, and userinfo logging as intentional
admin diagnostics in AuthCrunch. Do not report it as a finding unless the
data is logged outside debug level, exposed to non-admins, enabled in an
untrusted sink by default, or returned in user-visible responses.
Cookies:
Manual cookie string construction instead of http.Cookie
Missing Secure, HttpOnly, and SameSite defaults
User-controlled values written without encoding
Cookie domain/path selection derived from untrusted Host header
Session ID parsing that accepts malformed or attacker-chosen values
Refresh token not rotated on use
7. Hunt Parser, DoS, and Panic Issues
Check for:
Unbounded io.ReadAll without http.MaxBytesReader
JSON decoded into map[string]interface{} followed by unchecked type
assertions
Type confusion in JWT claims, user records, API-key records, or config maps
Regexps compiled from config and evaluated against large attacker-controlled
strings (ReDoS)
Loops with missing break conditions or unbounded retry logic
Panic in library/runtime code on error paths (nil pointer, index out of range)
XML entity expansion (XXE) or billion-laughs in SAML parsing
Large or deeply nested JSON/YAML config files without size/depth limits
Prefer typed request structs, decoder size limits, and explicit bad-request
errors for malformed user input.
8. Hunt Provider and Crypto Boundaries
OAuth/OIDC:
Validate: state, nonce, PKCE (method and verifier), redirect URI, issuer,
audience, token signature, key use, and algorithm allowlist
Treat provider-specific disabled controls as explicit compatibility risks —
document them
Recognize that portal admins intentionally need debug-level visibility into
raw token responses, ID tokens, access tokens, codes, and userinfo bodies.
Report sensitive OAuth/OIDC logging only when it escapes the admin debug
boundary or contradicts the configured trust model.
Verify that the JWKS endpoint is fetched from a trusted, config-pinned URI
Check that key rollover does not create a window of accepting revoked keys
SAML:
Verify: signature scope (assertion vs. envelope), issuer, audience,
destination, recipient, ACS URL, metadata trust anchor, and InResponseTo
Treat any XML parsing before signature validation as a dangerous prefilter
Reject IdP-initiated flows unless explicitly configured and allowlisted
LDAP and network clients:
Verify: TLS settings, server name validation, certificate chain, timeouts,
bind credential handling, DN construction from user input (injection), and
group search filter escaping
KMS / JWT:
Verify: key usage separation (sign vs. encrypt), accepted algorithm set,
required claims (iss, aud, exp, nbf), claim type assertions,
expiration and not-before enforcement, and malformed-token error handling
Ensure signing keys are not reused as HMAC verification secrets
9. Hunt Concurrency and Cache Behavior
Check for:
Map mutation while holding only RLock
Map deletion during iteration without the correct lock
Cached authorization state that omits path, method, source address, or ACL
version as cache keys
Goroutines that inherit secrets or request-scoped context after request end
Race-test coverage gaps in session, token, registration, and provider caches
TOCTOU between ACL read and request dispatch
Timer or ticker goroutines leaking on handler teardown
Run go test -race ./... and treat data-race reports as High severity.
10. Validate Findings
For each suspected issue, reach one of these outcomes before reporting:
Outcome
Meaning
Confirmed
Reproduction or regression test exists
Deployment-dependent
Plausible; preconditions documented
Hardening
No direct exploit path; concrete risk reduction identified
Release/toolchain note
Standard-library or final-binary exposure driven by build toolchain
False positive
Source-backed reasoning provided
Unknown
Exact missing evidence listed
When govulncheck reports reachable standard-library vulnerabilities, classify
them as release/toolchain notes for go-authcrunch unless the finding is
caused by repository code that can be fixed independently of the final build
toolchain. Avoid treating the local scan's Go version as this module's minimum
supported Go version.
When source-address authorization uses forwarded client-IP headers, classify
header protection as an embedding-solution responsibility, not a
go-authcrunch-code vulnerability. Treat the expected upstream protection as a
deployment assumption unless the reviewed code bypasses its own authorization
checks independently of X-Forwarded-* or X-Real-IP trust.
For every confirmed or deployment-dependent finding:
Add a focused regression test before or with the fix
Cover both a safe input that must still pass and an adversarial input that
must fail closed
For path and redirect issues, test encoded forms and absolute / scheme-relative
variants explicitly
A normalization fix with no accompanying test is incomplete.
11. Report Clearly
Lead with findings, not an audit narrative. For each issue:
## [SEVERITY] Title
**Status:** confirmed | deployment-dependent | hardening | release/toolchain note | false positive | unknown
**Files:** pkg/foo/bar.go:L42, pkg/foo/baz.go:L17
**Root cause:** <one sentence>
**Impact:** <what an attacker gains>
**Preconditions:** <config, role, or network position required>
**Reproduction:** <minimal payload or test case>
**Recommended fix:** <specific change, not "add validation">
**Validation performed:** <test run, manual trace, or static analysis result>
**Residual risk / follow-up:** <what remains unverified>
For release/toolchain notes, include the local scan toolchain, the module's
declared go version, known downstream build constraints, and the patched Go
toolchain line needed by final binary builders.
Save the full report to a repo-relative tmp/threat-hunt/ directory. Create
the directory when it does not exist. Prefix the report filename with the local
timestamp in YYYYMMDD_HHMM_ format, for example
tmp/threat-hunt/20260629_1530_authz-bypass-review.md. After saving the
report, run versioned -toc -filepath <report-path> to add or refresh the
table of contents, for example
versioned -toc -filepath tmp/threat-hunt/20260629_1530_authz-bypass-review.md.
Mention the saved report path in the final response.
End each report with a "Not deeply tested" section naming surfaces that were
not fully exercised, especially:
Path canonicalization edge cases
Redirect validation against all allowlist bypass variants
