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Rule Reference

SEC698lintai-ai-securitystablejsonwarn

MCP config: browser credential store exfiltration

MCP configuration command exfiltrates browser credential or cookie store data

Provider
lintai-ai-security
Surface
json
Scope
per_file
Tier
stable
Severity
warn
Confidence
high
Detection
structural
Remediation
message_only

Activation Model

Preset Membership

This rule is part of the builtin activation graph through these preset memberships.

basemembership
mcpmembership

Lifecycle

Stable Lifecycle Contract

State

stable_gated

Graduation rationale

Checks committed MCP launch paths for direct access to browser credential or cookie storage files combined with remote transfer behavior.

Deterministic signal basis

JsonSignals command-plus-args analysis over ArtifactKind::McpConfig for browser profile paths such as Chrome or Firefox state directories paired with secret-store files like `Cookies`, `Login Data`, `logins.json`, `key4.db`, `Web Data`, or `Local State`, combined with remote sinks such as `curl`, `wget`, `scp`, `rsync`, `nc`, or HTTP(S) endpoints.

Malicious corpus
mcp-command-local-data-exfil
Benign corpus
mcp-safe-basic
structured evidence required remediation reviewed
Canonical note

Structural stable rule intended as a high-precision check with deterministic evidence.

Nearby Signals

Related Rules

SEC301MCP config: shell trampolineMCP configuration shells out through sh -c or bash -cjsonstable
SEC302Config: insecure HTTP endpointConfiguration contains an insecure http:// endpointjsonstable
SEC303MCP config: credential env passthroughMCP configuration passes through credential environment variablesjsonstable
SEC304Config: TLS verification disabledConfiguration disables TLS or certificate verificationjsonstable
SEC305Config: hardcoded auth materialConfiguration embeds static authentication material in a connection or auth valuejsonstable
SEC309Config: literal secrets in configConfiguration commits literal secret material in env, auth, or header valuesjsonstable

Why It Matters ​

Browser credential and cookie stores can carry saved passwords and active sessions. A committed MCP launcher that sends them away is explicit theft behavior.

What Triggers ​

SEC698 matches committed MCP command paths that access browser profile directories together with secret-store files like Cookies, Login Data, logins.json, key4.db, Web Data, or Local State, and also transmit data to remote sinks such as curl, wget, scp, rsync, nc, or HTTP(S) endpoints.

False Positives ​

Normal committed MCP tooling should not collect and transmit browser credential databases. Any legitimate local inspection should be kept outside shared committed config.

Remediation ​

Remove network exfiltration of browser credential and cookie store data from the committed MCP launch path and keep browser profile data local.