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Miggo AIGenerate vendor-ready rules for the observed attack patterns, plus reasoning and safe deployment guidance
Miggo AIRoot Cause AnalysisThe vulnerability is an improper authentication issue in PraisonAI's LinearBot. The root cause is a 'fail-open' design in the webhook handling logic. The LinearBot._handle_webhook function would only verify the cryptographic signature of an incoming webhook if a LINEAR_WEBHOOK_SECRET was configured. If the secret was missing, the bot would skip the verification and process the request, allowing an unauthenticated attacker to forge webhook events and invoke the bot's agent. This was compounded by the LinearBot.start function, which would bind the listener to a public network interface (0.0.0.0) even in this insecure state. The provided patch corrects this by introducing a 'fail-closed' mechanism. It modifies _handle_webhook to reject requests with a 401 Unauthorized status if the signing secret is not configured, unless a specific environment variable (PRAISONAI_INSECURE_WEBHOOKS) is set to explicitly allow this behavior for development purposes.
praisonai.bots.linear.LinearBot._handle_webhooksrc/praisonai/praisonai/bots/linear.py
praisonai.bots.linear.LinearBot.__init__src/praisonai/praisonai/bots/linear.py
praisonai.bots.linear.LinearBot.startsrc/praisonai/praisonai/bots/linear.py
praisonai.cli.features.bots_cli.start_linearsrc/praisonai/praisonai/cli/features/bots_cli.py
| Package Name | Ecosystem | Vulnerable Versions | First Patched Version |
|---|---|---|---|
| praisonai | pip | >= 4.6.56, <= 4.6.58 | 4.6.59 |
2f9677abb2ea68eab864ee8b6a828fd0141612e1v4.6.57v4.6.56v4.5.50Sampled tags where the LinearBot component was not present:
v4.5.49v4.5.51v4.6.9v4.6.10Suggested affected range: LinearBot-bearing releases with the fail-open
signature behavior, at least 4.5.50 and >= 4.6.56, <= 4.6.58. The
component appears non-contiguously in sampled tags, so maintainers should
confirm the exact packaged version history before publishing a final range.
LinearBot.__init__() accepts an empty signing secret and falls back to an
empty environment value:
self._signing_secret = signing_secret or os.environ.get("LINEAR_WEBHOOK_SECRET", "")
start() treats the missing secret as a warning instead of refusing to expose
the webhook listener:
if not self._signing_secret:
logger.warning("LINEAR_WEBHOOK_SECRET not set - webhook signatures will not be verified")
self._site = web.TCPSite(self._runner, "0.0.0.0", self._webhook_port)
_handle_webhook() only verifies the request if the secret is truthy:
if self._signing_secret:
signature = request.headers.get("Linear-Signature", "")
if not self._verify_signature(raw_body, signature):
return web.Response(status=401, text="Invalid signature")
With no secret configured, the code continues to JSON parsing, accepts a caller
supplied webhookTimestamp, reads the caller supplied Linear-Event header,
and schedules processing:
event_type = request.headers.get("Linear-Event", "")
task = asyncio.create_task(self._process_webhook(event_type, body))
return web.Response(status=200, text="OK")
For AgentSession, the forged body is routed to the agent:
if event_type == "AgentSession":
await self._handle_agent_session(body)
...
response = await self._session_mgr.chat(self._agent, user_id, message.content)
await self._send_comment(...)
The CLI has the same fail-open posture: start_linear() loads
LINEAR_WEBHOOK_SECRET, prints a warning when it is missing, then reports a
public http://0.0.0.0:<port>/webhook endpoint with verification disabled.
PraisonAI's Linear Bot documentation tells operators to set
LINEAR_WEBHOOK_SECRET, pass it to praisonai bot linear, copy the Linear
webhook signing secret, and use it for HMAC-SHA256 verification. The same page
says missing secrets disable signature verification, while its best-practices
section says webhook secrets ensure authenticity.
Linear's webhook documentation says receivers should ensure requests were sent
by Linear by verifying the Linear-Signature HMAC over the raw body, then
checking that webhookTimestamp is recent. The timestamp check alone is not an
authentication boundary because an attacker can supply a current timestamp in a
forged body.
The implementation itself also confirms the intended boundary: when a secret is configured, missing and bad signatures are rejected before agent dispatch. The bug is the missing-secret fail-open mode on a public webhook server, not the signature algorithm.
Run against the latest observed release checkout:
python3 submission-bundle/praisonai-prai-cand-013-linear-webhook-signature-fail-open/poc/pov_prai_cand_013_linear_webhook_signature_fail_open.py --repo artifacts/repos/praisonai-v4.6.58
Expected output includes:
{
"candidate": "PRAI-CAND-013",
"ok": true,
"cases": {
"no_secret_unsigned_forged_webhook": {
"http_status": 200,
"signing_secret_configured": false,
"session_calls": [
{
"user_id": "linear-system",
"content": "Issue: Forged Linear AgentSession event\n\nPRAI-CAND-013 local forged webhook payload"
}
],
"sent_comments": [
{
"issue_id": "issue-prai-cand-013",
"comment": "agent response",
"session_id": "prai-cand-013-session"
}
]
},
"secret_missing_signature_control": {
"http_status": 401,
"session_calls": []
},
"secret_bad_signature_control": {
"http_status": 401,
"session_calls": []
},
"secret_valid_signature_control": {
"http_status": 200,
"session_calls": [
{
"user_id": "linear-system"
}
]
}
}
}
Stored evidence:
evidence/pov-v4.6.58.jsonevidence/pov-live-main-v4.6.58.jsonevidence/pov-current-head.jsonevidence/version-sweep.tsvIf a PraisonAI operator starts LinearBot with a Linear token but omits
LINEAR_WEBHOOK_SECRET, any network caller that can reach the webhook endpoint
can spoof Linear webhook events and invoke the configured agent through the
Linear integration.
For the AgentSession event path, this lets the attacker supply issue title and
description content that becomes the agent input. Depending on the configured
agent and tools, this can cause unauthorized LLM/tool execution, consume paid
model quota, create or update Linear comments under the bot identity, and drive
the bot into workflows intended only for authenticated Linear events.
This report does not claim arbitrary code execution by default. The concrete boundary crossed is unauthenticated remote agent invocation through a forged Linear webhook.
Fail closed for public webhook listeners:
LINEAR_WEBHOOK_SECRET is missing, unless an
explicit development-only option such as
--insecure-skip-webhook-signature-verification is provided._handle_webhook(), reject requests when no signing secret is configured
instead of silently skipping verification.401;401;401;