GHSA-w72w-9qmj-c9qm: Medium severity go/github.com/anycable/anycable vulnerability
Summary The telemetry subsystem embeds a hardcoded auth token ("secret") in the public source and transmits raw CLI arguments—including --secret, --jwtsecret, and --httprpcsecret values—to a third-party telemetry endpoint.
Details In telemetry/config.go line 12, var authToken = "secret" is committed in the public repository and used to authenticate to https://telemetry.anycable.io. In telemetry/telemetry.go, clusterFingerprint() (line 320) calls both anycableFileConfig(c.ConfigFilePath) (line 333), which reads the full TOML config file contents, and anycableCLIArgs() (line 402), which reads os.Args[1:] verbatim—including any --secret=..., --jwtsecret=..., --httprpcsecret=... arguments. Both raw values are passed to generateDigest() (line 373), meaning the actual secret strings flow through the code path and are included in telemetry data sent to the third-party server. Since the hardcoded authToken = "secret" is public, any attacker who can perform DNS hijacking or is positioned on the network path can intercept and read the telemetry payload containing operator credentials.
PoC 1. Read telemetry/config.go in the public repo to find authToken = "secret". 2. Set up a DNS spoof for telemetry.anycable.io pointing to an attacker-controlled server. 3. Start anycable-go with --secret=my-production-secret. 4. The server sends a POST to the attacker's endpoint with the telemetry JSON payload. The clusterFingerprint field contains data derived from raw os.Args including --secret=my-production-secret.
Impact In MITM/DNS-hijack scenarios, production secrets (JWT secrets, broadcast keys, RPC auth) are exposed to third parties. The hardcoded authToken = "secret" provides no protection since it is known to anyone reading the open-source code.
Fix 1. Remove the hardcoded authToken from source; generate or require operator configuration at build time or deployment time. 2. Remove anycableCLIArgs() from the fingerprint computation, or sanitize it to exclude values of secret-bearing flags before hashing. 3. Add a documented opt-out mechanism for telemetry.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
go/github.com/anycable/anycableto a version that resolves this vulnerability.Fixed in 1.6.15 - Remove
Remove
anycable-go telemetry hardcoded authTokenfrom your environment.Remove the hardcoded auth token string (telemetry/config.go `var authToken = "secret"`) from source code and require operator/build-time/deployment-time configuration to provide the telemetry authentication token instead.
- Configuration
Add and document an opt-out mechanism for telemetry so operators can disable telemetry collection/sending when desired.
anycable-go telemetry opt-out mechanism for telemetry = enabled/available (documented opt-out) - Configuration
Remove anycableCLIArgs() from the fingerprint computation, or sanitize it so it excludes values for secret-bearing CLI flags before hashing (e.g., exclude --secret, --jwt_secret, --http_rpc_secret from the os.Args-based data used for clusterFingerprint()).
anycable-go telemetry clusterFingerprint computation = exclude secret-bearing flags - Compensating control
Mitigate DNS-hijack/MITM scenarios against telemetry by preventing or detecting spoofing of `telemetry.anycable.io` (e.g., ensure DNS integrity and restrict/monitor outbound/egress paths to the telemetry endpoint).
- Operational
After making changes, restart anycable-go so new telemetry payloads no longer include raw secret-bearing CLI argument values in clusterFingerprint/telemetry data, and ensure any operator credentials used in telemetry-related flags are handled according to the new telemetry behavior.
Event History
Frequently Asked Questions
What level of attacker access is needed to obtain exposed credentials?
An attacker needs to perform DNS hijacking or be positioned on the network path to intercept telemetry sent to the third-party endpoint. The publicly committed authentication token is not secret and therefore does not provide meaningful protection for the telemetry payload.
Which secrets should be considered at risk?
Values supplied through --secret, --jwt_secret, and --http_rpc_secret command-line arguments are included verbatim in the telemetry code path. The full TOML configuration file is also read and passed through that path, so credentials stored in that file may be exposed as well.
How can an operator identify whether their deployment may be sending sensitive data?
Review the AnyCable startup arguments for --secret, --jwt_secret, or --http_rpc_secret, and inspect the configured TOML file for credentials. Deployments that provide these values through CLI arguments or the configuration file can have those values processed by telemetry.