{"id":"GHSA-hfxh-rjv7-2369","summary":"Uptime Kuma Authenticated remote code execution via TailscalePing","details":"### Summary\n\nThe `runTailscalePing` method of the `TailscalePing` class injects the `hostname` parameter inside a shell command, leading to a command injection and the possibility to run arbitrary commands on the server.\n\n### Details\n\nWhen adding a new monitor on Uptime Kuma, we can select the \"Tailscale Ping\" type. Then we can add a hostname and insert a command injection payload into it. The front-end application requires that the field follow a specific pattern, this validation only happens on the front-end and can be removed by removing the attribute `pattern` on the `input` element.\n\nhttps://github.com/louislam/uptime-kuma/blob/dc4242019331e65a79ac16deef97510144e01b12/server/monitor-types/tailscale-ping.js#L40-L46\n\nWe can finally add the new monitor and observe that our command is being executed.\n\n**NOTE:** When using Uptime Kuma inside a container, the \"TailScale Ping\" type is not visible. We can fake this information by intercepting WebSocket messages and set the `isContainer` option to `false`.\n\n### PoC\n\n* Authenticate.\n* Create a new monitor.\n* Select the TailScale Ping type (if not visible, see the note in the details section).\n* Insert the command injection payload inside the `hostname` field. (for example `$(id \u003e&2)`)\n* Remove the `pattern` requirement on the field.\n* Save and start the monitor.\n\n### Impact\n\nAn authenticated user can execute arbitrary command on the server running Uptime Kuma.\n\n### Remediation\n\nThere are other command execution in the codebase, they use a method `spawn` from the `child_process` module which does not interpret the command as a shell command, the same thing should be done here.\n\n**NOTE:** The Tailscale CLI seems to support the `--` sequence. It should be used between the `ping` subcommand and the `hostname` argument to avoid argument injection.","modified":"2023-11-27T17:25:11Z","published":"2023-11-27T17:25:11Z","database_specific":{"nvd_published_at":null,"cwe_ids":[],"severity":"MODERATE","github_reviewed":true,"github_reviewed_at":"2023-11-27T17:25:11Z"},"references":[{"type":"WEB","url":"https://github.com/louislam/uptime-kuma/security/advisories/GHSA-hfxh-rjv7-2369"},{"type":"PACKAGE","url":"https://github.com/louislam/uptime-kuma"}],"affected":[{"package":{"name":"uptime-kuma","ecosystem":"npm","purl":"pkg:npm/uptime-kuma"},"ranges":[{"type":"SEMVER","events":[{"introduced":"1.23.0"},{"fixed":"1.23.7"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2023/11/GHSA-hfxh-rjv7-2369/GHSA-hfxh-rjv7-2369.json","last_known_affected_version_range":"\u003c= 1.23.6"}}],"schema_version":"1.9.0"}