After the initial quick shot (see this post) we decided to have a closer look. And some more stuff turned up.
After decompiling the integrated java stuff we stumbled about hard coded server credentials:
package Idonttell;
public abstract interface Idonttell
{
public static final boolean debug = false;
public static final boolean auth = true;
public static final String SMTP_SERVER = "Idonttell.openlimit.com";
public static final String SMTP_USER = "Idonttell@Idonttell.openlimit.com";
public static final String SMTP_PASSWORD = "Idonttell";
public static final String SEND_FROM = "Idonttell@Idonttell.openlimit.com";
public static final String[] SEND_TO = { "buergerclient.it-solutions@Idonttell.com" };
public static final String MAIL_HEADER_FIELD = "OpenLimitErrorMessage";
public static final String MAIL_HEADER_FIELD_PROP = "yes";
}
The AusweisApp uses these credentials to authenticate against a mail server and send error reports to a dedicated email address. The server was accessible from the internet and services like SMTP, FTP and SSH were running. Following the principles of responsible disclosure the vendor was contacted and responded within a few hours, so the servers are already protected against any kind of misuse. So save your time and keep the german hacking laws in mind ;-).
Nevertheless doing code reviews for years, one point on the checklist is secure storage of data. Any kind of secrets should never be included directly in the source code and never ever in cleartext like it was done in the AusweisApp. These secrets can be accessed quite easily, so how useful is an authentication feature, if everybody knows the password ;-)?
This leaves me scratching my head. Maybe I was a bit overhasty when writing this 😉
Ok, getting serious again, this finding is another proof that the concept of rating closed source software based on well chosen metrics can help to determine the trustworthiness of software, because building secure software means that you develop with security in mind and this is what these metrics are measuring.
have a nice week and be aware of more updates as our research continues. We’re investigating another interesting possible flaw …
Michael