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10 Secret Patterns I Check for First in Any Repo Audit

The secret audit that finds the real problems checks the same ten patterns in every repository, and the order is the point, because the order is ranked by how often each pattern shows up in a real codebase and how expensive the miss is. The audit is not a scan of everything, which takes a while and produces noise; it is a directed pass over the ten places where secrets actually live, and it takes five minutes, which is the part that makes it a habit instead of a project. The scanner automates the pass, but knowing the ten patterns is what lets you read the results instead of trusting them.
The top of the list is the cloud provider key prefix, the most common leak by a wide margin, and the check is the pattern match against the known prefix in every file the build reads. Next is the git token, the one that can push code, which is the most dangerous shape to find in a repository. The database connection string is third, because it is the credential that the rest of the application assumes is private, and it is the one that ends up in the compose file. The remaining seven are in the section below, each with the file type it lives in, the pattern to look for, and the rotation path when the pattern matches, because the audit without the rotation step is a list of problems, and the audit with the rotation step is a closed loop.

The list is the format, and the format is the promise: each entry is one thing, one use case, and one honest note, and the three are the unit the list is made of. The entries are ordered by the weight they carry in actual use, not by the order they were discovered, because the discovered order is the story and the weight order is the tool. The entries come from dotguard, Scan .env files, config files, and source code for exposed secrets. Zero dependencies, JSON reports, 1000+ files in seconds., and the tool is the context for the list, because the list is the tool's shape made explicit, and the explicit is the part the feature page does not do, and the does-not-do is what the list is for. The section below is the list, and the list is the section.

One Line in GitHub Actions

The entire CI integration is one step: a run line that invokes the scanner via npx. No service container, no token to configure, no daemon. Every push gets a full scan, and the build fails if a secret is found, which means the secret never reaches the default branch. The beauty of the one-line integration is the maintenance cost: there is nothing to update, no version to pin, and no vendor to renew. When a security control costs one line of workflow file, the only question is why it is not already there. That is the bar every pre-merge security control should meet, and the scanner was designed to meet it on purpose. The one line is also the onboarding story: new contributors see the check in the workflow file, understand what it is doing, and never have to be told to run it. The pipeline is the policy, and the policy is one line long.

The JSON Report That CI Can Actually Use

A security tool is only as good as its integration surface, and the scanner's is a JSON report. Run it with the report flag and you get a machine-readable list of every finding: file, line, rule, severity. Exit codes are meaningful, so a pipeline can fail the build on any finding without parsing colored terminal output. That design decision pays off in the boring way: the tool fits into CI or a local pre-push script with zero glue code. When the report is data instead of text, other tools can consume it — a dashboard, a chat alert, a compliance export. Security tooling that cannot be integrated is a demo, not infrastructure. The JSON report is the part of the design that turns a one-person tool into a team habit, and it costs nothing to use: the same command, one extra flag, and the output becomes something the rest of the system can act on.

False Positives Are the Real Cost of a Scanner

Every secret scanner has to make a tradeoff: miss a real key, or flag a false one. The scanner leans toward flagging, and the price is occasional false positives — an encoded blob that looks like a key, a test fixture with a fake credential, a documentation example that uses a real-looking prefix. That is why the output includes the file, the line, and the matched rule: the cost of verifying a finding should be five seconds, not a forensic exercise. A scanner with zero false positives that also misses real keys is a liability, not a tool. Budget a minute per finding, verify, rotate if it is real, and note the known test values so the team stops re-checking them. The loop is the product. Over time the false-positive list becomes its own artifact — a record of the places in the codebase that look like secrets and are not, which is useful information in its own right, because it maps the codebase's sensitive-looking surfaces.

The Exit Code Is the Integration

The scanner's interface to the machine is the exit code, and the exit code is the part that makes it CI-ready without any glue. A clean scan exits zero, a scan with findings exits nonzero, and the nonzero is what the pipeline turns into a failure, and the failure is what blocks the push. The pre-push hook uses the same code: the hook runs the scan, and the push goes through only if the exit code is zero. The JSON report is the second interface, for the things that consume data instead of pass/fail: the dashboard that charts findings over time, the chat alert that posts the file and the line, the compliance export that needs the record. The two interfaces cover the two consumers, the pipeline and the person, and the coverage is the design. A tool that needs a wrapper script to be useful in CI is a tool that will not be in CI, because the wrapper is the step that does not get written, and the not-written is the check that does not run.

The Files It Reads, and the Ones It Skips

The scanner's file coverage is the difference between the scan and the audit, and the coverage list is worth knowing. It reads the environment files, the config files in the common formats, the compose files, the YAML under the deploy directories, the JSON configs, and the source code, because the source is where the debug paste lives. It skips the directories that are noise by definition: the dependency folders, the build output, the lockfiles, because the dependency folders are the supply chain and the supply chain is audited separately, and the build output is derived and the derived is not the source of truth. The skip list is the tuning that makes the scan fast on a monorepo, and the fast scan is what runs often enough to matter. The coverage list is in the documentation, and the documentation is the thing to read once, because the one read is what separates the person who trusts the scan from the person who wonders what it missed, and the wondering is what stops the trust.

The False Positive Conversation

Every scanner has false positives, and the honest relationship with them is the part that keeps the tool in the workflow. The fixtures are the main source: the test that asserts against a fake key, the README example that shows a token shape, the mock that returns a secret-looking string. The false positive is not a bug in the scanner, it is the scanner doing its job on data that looks like the job, and the cost of the false positive is the five-second check, which is the cost the tool is designed around. The known-false-positive list is the management: the findings you have already classified stay classified, and the classification is what the report's rule field supports, because the rule tells you the shape that fired, and the shape is what the fixture is. The conversation to have with the team is not about removing the false positives, it is about budgeting for them: the five seconds each, and the list that grows, and the list that makes the next triage faster. The scanner that has no false positives is the scanner that misses the custom key, and the custom key is the one that matters.

The Team-Wide Hook: Distributing the Habit

Personal hooks die with the person who set them up. The pattern that actually works is distribution: put the scan in a hook that lives in the repository itself, committed to version control, so every clone gets the behavior automatically. A new developer clones the repository, runs their first command, and the scanner is already there. Nobody has to be told, nobody has to remember, and the behavior cannot be forgotten because it is part of the repository. This is the difference between a tool and a practice: a tool is what one person runs, a practice is what the repository does to everyone. The scanner is small enough that the distributed version costs nothing to maintain — one file, one command, zero configuration — which is exactly the size at which a team habit becomes cheaper than the individual habit it replaces. The repository becomes the enforcer, and enforcement by repository is the only enforcement that survives turnover.

What Zero Dependencies Buys You in a Security Tool

A security tool has a special trust problem: you are asking it to read your most sensitive files. The natural question is what the tool itself trusts. For this one, the answer is nothing. No dependencies, no network calls, no telemetry, no update daemon. It reads files, matches patterns, and writes a report. That matters in the places where security tooling gets blocked: restricted CI runners, air-gapped builds, compliance environments that require an audit of every third-party package in the pipeline. A single-file scanner with zero dependencies is auditable in an afternoon by a security reviewer who would never approve a forty-package tree. In security, small is not a feature. Small is the product. The auditability is the trust model: you can read the whole thing, you can verify what it matches, and you can be confident that the thing reading your secrets is not also phoning home with them. That confidence is not a nice property of the design; it is the design.

How the Scan Actually Works

The scanner looks for the patterns that real secrets actually take. Cloud provider keys start with a known prefix, Git tokens start with a known prefix, messaging platform tokens have a known shape, payment processor live keys have a known prefix, and web tokens start with a known base64 header. It also checks for high-entropy strings assigned to suspicious variable names — password, token, secret, key — because the values do not always follow the format, but variable names are a reliable signal. The scan covers environment files, config files, and source code, and it reports the file, the line, and the matched pattern so a human can verify in seconds rather than minutes. It is deliberately a detection tool, not a verdict tool: it finds candidates, a human confirms, and the key gets rotated either way. That division of labor is what keeps false positives from becoming noise fatigue.

Rotation Beats Detection, Every Time

There is a comfortable misconception that finding a secret is the win. It is not. The win is the key that no longer works. A detected secret that stays valid is a secret that is still leaking; the only difference is that now you know about it, which is a strange kind of liability. The workflow that matters is: scan, confirm, rotate, and then scan again to confirm the rotation happened and the old value is gone from the working tree or accepted as a known dead value. Rotation is boring, it touches other teams, and it is the step everyone skips. A detection tool that makes rotation feel like a natural next step — by giving you the exact file and line, so the fix is a two-minute job — is doing more than pattern matching. The finding is a ticket, and the ticket's definition of done is the rotated key, not the closed alert. Designing the tool around that definition of done is what separates a scanner from a security workflow.

Two Rhythms: The Daily Path and the Quarterly Tree

The scanner runs on two cadences, and the two cadences are the practice. The daily one is the targeted scan: the path pointed at the directory that changed, the service that touched the config, the deploy folder that holds the real credentials. The targeted scan is fast enough to run before the push, and the fast is what makes it the reflex. The quarterly one is the recursive sweep: the flag pointed at the whole projects directory, the tree that includes the forgotten experiment and the demo repository and the fork that nobody maintains. The sweep is the deep clean, and the deep clean is what catches the leak that is already old, because the old leak is the one the targeted scan never points at, and the never-pointed-at is where the leak waits. The same command, the same rules, two scopes, two rhythms. The monorepo does not need a different tool for the two cadences, it needs the same tool aimed at the two scopes, and the aiming is the practice, and the practice is what the scanner's flags exist to make cheap.

The takeaway

The list is the section, and the section is done, which means the entries are the content and the content is the part the reader scans. dotguard is the tool behind the list: Scan .env files, config files, and source code for exposed secrets. Zero dependencies, JSON reports, 1000+ files in seconds. The install line is npx @wuchunjie/dotguard, and the line is the part that makes the entries runnable, because the runnable is what the list entry promises and the promise is the part the reader checks. The repository is https://github.com/wuchunjie00/dotguard, and the repository is where the next entry goes, because the next-entry is the part the list that stops growing loses, and the loses is what the maintained list does not.

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