{"id":"GHSA-mj8x-cpr8-x39h","summary":"Remote code execution in Apache Tapestry","details":"A critical unauthenticated remote code execution vulnerability was found all recent versions of Apache Tapestry. The affected versions include 5.4.5, 5.5.0, 5.6.2 and 5.7.0. The vulnerability I have found is a bypass of the fix for CVE-2019-0195. Recap: Before the fix of CVE-2019-0195 it was possible to download arbitrary class files from the classpath by providing a crafted asset file URL. An attacker was able to download the file `AppModule.class` by requesting the URL `http://localhost:8080/assets/something/services/AppModule.class` which contains a HMAC secret key. The fix for that bug was a blacklist filter that checks if the URL ends with `.class`, `.properties` or `.xml`. Bypass: Unfortunately, the blacklist solution can simply be bypassed by appending a `/` at the end of the URL: `http://localhost:8080/assets/something/services/AppModule.class/` The slash is stripped after the blacklist check and the file `AppModule.class` is loaded into the response. This class usually contains the HMAC secret key which is used to sign serialized Java objects. With the knowledge of that key an attacker can sign a Java gadget chain that leads to RCE (e.g. CommonsBeanUtils1 from ysoserial). Solution for this vulnerability: * For Apache Tapestry 5.4.0 to 5.6.2, upgrade to 5.6.3 or later. * For Apache Tapestry 5.7.0, upgrade to 5.7.1 or later.","aliases":["CVE-2021-27850"],"modified":"2024-12-02T05:47:35.826691Z","published":"2021-06-16T17:33:19Z","database_specific":{"github_reviewed":true,"cwe_ids":["CWE-502","CWE-922"],"nvd_published_at":"2021-04-15T08:15:00Z","github_reviewed_at":"2021-04-19T21:38:56Z","severity":"CRITICAL"},"references":[{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2021-27850"},{"type":"WEB","url":"https://issues.apache.org/jira/browse/TAP5-2663"},{"type":"WEB","url":"https://lists.apache.org/thread.html/r237ff7f286bda31682c254550c1ebf92b0ec61329b32fbeb2d1c8751%40%3Cusers.tapestry.apache.org%3E"},{"type":"WEB","url":"https://security.netapp.com/advisory/ntap-20210528-0002"},{"type":"WEB","url":"http://www.openwall.com/lists/oss-security/2021/04/15/1"}],"affected":[{"package":{"name":"org.apache.tapestry:tapestry-core","ecosystem":"Maven","purl":"pkg:maven/org.apache.tapestry/tapestry-core"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"5.4.0"},{"fixed":"5.6.3"}]}],"versions":["5.4.0","5.4.1","5.4.2","5.4.3","5.4.4","5.4.5","5.5.0","5.5.0-beta-3","5.6.0","5.6.1","5.6.2"],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2021/06/GHSA-mj8x-cpr8-x39h/GHSA-mj8x-cpr8-x39h.json"}},{"package":{"name":"org.apache.tapestry:tapestry-core","ecosystem":"Maven","purl":"pkg:maven/org.apache.tapestry/tapestry-core"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"5.7.0"},{"fixed":"5.7.1"}]}],"versions":["5.7.0"],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2021/06/GHSA-mj8x-cpr8-x39h/GHSA-mj8x-cpr8-x39h.json"}}],"schema_version":"1.7.3"}