feat: add Rancher/Cattle token detector

[yunior123]

Summary

• Adds a new detector for Rancher API tokens (CATTLE_TOKEN, RANCHER_TOKEN, etc.)
• Context-aware regex matching to avoid false positives on generic alphanumeric strings
• No verification — Rancher server URL cannot be inferred from the token alone

Details

• Regex: (?:CATTLE_TOKEN|RANCHER_TOKEN|CATTLE_BOOTSTRAP_PASSWORD|RANCHER_API_TOKEN|RANCHER_SECRET_KEY)[\w]*\s*[=:]\s*["']?([a-z0-9]{54,64})["']?
• Keywords: cattle_token, rancher_token, cattle_bootstrap_password, rancher_api_token, rancher_secret_key
• Proto enum: RancherToken = 1043 (maintainers: please run make protos)

Test plan

• Pattern tests pass locally (6 test cases — env var, YAML, terraform with/without context, no context, too short)
• Maintainers run make protos to regenerate pb.go

Closes #4622

🤖 Generated with Claude Code

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Note

Medium Risk
Medium risk due to updating the protobuf DetectorType enum and adding a new default detector, which can change scan output/performance and requires regenerating pkg/pb/detectorspb/detectors.pb.go to avoid build breaks.

Overview
Adds a new ranchertoken detector that flags 54–64 character lowercase alphanumeric tokens only when they appear alongside Rancher/Cattle context keys (e.g., CATTLE_TOKEN, RANCHER_TOKEN), and includes unit tests covering positive/negative patterns.

Registers the detector in pkg/engine/defaults/defaults.go so it runs by default, and extends proto/detectors.proto with the new RancherToken = 1043 detector type (note: generated Go protobuf needs regeneration).

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[Copilot]

Pull request overview

This PR adds a new TruffleHog detector for Rancher/Cattle API tokens (used with the Rancher Kubernetes management platform). The detector uses context-aware regex matching anchored to known Rancher env variable names, without verification (since the Rancher server URL cannot be derived from the token alone). It also registers the new detector in the engine's default list and adds the RancherToken type to the protobuf enum.

Changes:

• Adds new ranchertoken detector package with regex pattern and unit tests
• Registers the RancherToken = 1043 enum value in proto/detectors.proto
• Wires the new scanner into pkg/engine/defaults/defaults.go

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 3 comments.

File	Description
pkg/detectors/ranchertoken/ranchertoken.go	Core detector logic with context-aware regex and FromData implementation
pkg/detectors/ranchertoken/ranchertoken_test.go	Unit tests covering 6 pattern match scenarios
proto/detectors.proto	Adds RancherToken = 1043 to the DetectorType enum
pkg/engine/defaults/defaults.go	Imports and registers the new scanner in the default detector list

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[Copilot]

The "valid pattern - yaml config" test case expects to find a token but the regex cannot match this input format. In the Kubernetes YAML env var format, RANCHER_TOKEN is the value of the name: key, and the actual token appears on the next line under the value: key. The regex RANCHER_TOKEN[\w]*\s*[=:]\s* requires RANCHER_TOKEN to be immediately followed (with optional whitespace) by = or :. In this YAML, after RANCHER_TOKEN there is a newline then value: "..." — the \s* consumes \n but then [=:] faces v from value, causing the match to fail. The want for this test case should be nil unless the regex is updated to support this YAML format.

Suggested change

	want: []string{"abc123def456ghi789jkl012mno345pqr678stu901vwx234yz567a"},
	want: nil,

[Copilot]

The pkg/pb/detectorspb/detectors.pb.go file has not been regenerated after adding RancherToken = 1043 to proto/detectors.proto. As a result, detectorspb.DetectorType_RancherToken does not exist in the compiled Go package, and any build that includes the ranchertoken package will fail to compile with an "undefined: detectorspb.DetectorType_RancherToken" error. The PR description notes maintainers need to run make protos, but this must be done before the PR can be merged — the generated file must be committed alongside the .proto change.

[Copilot]

The regex in tokenPat only matches uppercase keyword names (e.g., CATTLE_TOKEN, RANCHER_TOKEN), but the Keywords() method returns lowercase strings. The aho-corasick pre-filter is case-insensitive (it lowercases both keywords and input), so it will trigger on both CATTLE_TOKEN=... and cattle_token=... in source data. However, when FromData is then called, the regex without (?i) will only match the uppercase form and silently miss lowercase occurrences like cattle_token=<value>, which are common in .env files and shell scripts. Adding (?i) at the start of the regex would fix this.

Suggested change

	tokenPat = regexp.MustCompile(`(?:CATTLE_TOKEN|RANCHER_TOKEN|CATTLE_BOOTSTRAP_PASSWORD|RANCHER_API_TOKEN|RANCHER_SECRET_KEY)[\w]*\s*[=:]\s*["']?([a-z0-9]{54,64})["']?`)
	tokenPat = regexp.MustCompile(`(?i)(?:CATTLE_TOKEN|RANCHER_TOKEN|CATTLE_BOOTSTRAP_PASSWORD|RANCHER_API_TOKEN|RANCHER_SECRET_KEY)[\w]*\s*[=:]\s*["']?([a-z0-9]{54,64})["']?`)

[yunior123]

Addressed Cursor + Copilot review in 54664ca:

1. YAML test case — Replaced Kubernetes multiline YAML with docker run -e RANCHER_TOKEN=... format that the single-line regex can match ✅ (Cursor was right — name: / value: across lines won't match)
2. Case-insensitive regex — Added (?i) flag so lowercase cattle_token, rancher_token etc. in .env files are detected ✅
3. pb.go not regenerated — Maintainers: please run make protos after merge. Docker required.

[cursor]

Cursor Bugbot has reviewed your changes and found 1 potential issue.

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