CVE-2020-5222: Opencast kernel Hard-Coded Key Used For Remember-me Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-mh8g-hprg-8363",
  "modified" : "2021-10-20T18:03:56Z",
  "published" : "2020-01-30T21:21:44Z",
  "aliases" : [ "CVE-2020-5222" ],
  "summary" : "Hard-Coded Key Used For Remember-me Token in Opencast",
  "details" : "### Impact\n\nThe security configuration in `etc/security/mh_default_org.xml` enables a remember-me cookie based on a hash created from the [username, password, and an additional system key](https://docs.spring.io/spring-security/site/docs/3.0.x/reference/remember-me.html). Opencast has hard-coded this system key in the large XML file and never mentions to change this, basically ensuring that all systems use the same key:\n\n```xml\n<sec:remember-me key=\"opencast\" user-service-ref=\"userDetailsService\" />\n```\n\nThis means that an attacker getting access to a remember-me token for one server can get access to all servers which allow log-in using the same credentials without ever needing the credentials. For example, a remember-me token obtained from develop.opencast.org can be used on stable.opencast.org without actually knowing the log-in credentials.\n\nSuch an attack will usually not work on different installations – assuming that safe, unique passwords are used – but it is basically guaranteed to work to get access to all machines of one cluster if a token from one machine is compromised.\n\n### Patches\n\nThis problem is fixed in Opencast 7.6 and Opencast 8.1\n\n### Workarounds\n\nWe strongly recommend updating to the patched version. Still, as a workaround for older versions, in `etc/security/mh_default_org.xml`, set a custom key for each server:\n\n```xml\n<sec:remember-me key=\"CUSTOM_RANDOM_KEY\" user-service-ref=\"userDetailsService\" />\n```\n\n### References\n\n- [Relevant lines in the security configuration](https://github.com/opencast/opencast/blob/161ee619382f144dc35eea211fc6b556025b98e1/etc/security/mh_default_org.xml#L335-L336)\n- [Spring Security Remember-Me Authentication Documentation](https://docs.spring.io/spring-security/site/docs/3.0.x/reference/remember-me.html#remember-me-hash-token)\n\n### For more information\nIf you have any questions or comments about this advisory:\n- Open an issue in [opencast/opencast](https://github.com/opencast/opencast/issues)\n- For security-relevant information, email us at [security@opencast.org](mailto:security@opencast.org)\n\n### Thanks\nThanks to @LukasKalbertodt for reporting the issue.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:N/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "org.opencastproject:opencast-kernel"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "7.6"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "org.opencastproject:opencast-kernel"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "8.0"
      }, {
        "fixed" : "8.1"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/opencast/opencast/security/advisories/GHSA-mh8g-hprg-8363"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2020-5222"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/opencast/opencast/commit/1a7172c95af8d542a77ae5b153e4c834dd4788a6"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-798" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2020-01-30T20:48:17Z",
    "nvd_published_at" : null
  }
}