When X11 Forwarding is enabled, due to improper use of X11 authentication credentials. An exploit can be executed due to arbitrary xauth commands on the remote host. Dropbear SSH running on the remote host prior to version 2016.74 are affected by the following vulnerabilities:
- A format string flaw exists due to improper handling of string format specifiers (e.g., %s and %x) in usernames and host arguments. An unauthenticated, remote attacker can exploit this to execute arbitrary code with root privileges. (CVE-2016-7406).
- A flaw exists in dropbearconvert due to improper handling of specially crafted OpenSSH key files. An unauthenticated, remote attacker can exploit this to execute arbitrary code. (CVE-2016-7407)
- A flaw exists in dbclient when handling the -m or -c arguments in scripts. An unauthenticated, remote attacker can exploit this, via a specially crafted script, to execute arbitrary code. (CVE-2016-7408)
- A flaw exists in dbclient or dropbear server if they are compiled with the DEBUG_TRACE option and then run using the -v switch. A local attacker can exploit this to disclose process memory. (CVE-2016-7409)