Hi all, Dropbear 2016.74 is released. This includes fixes for a few security issues. Further details will be published by Beyond Security in a week or so, I will update CVE numbers when available.
Downloads are at https://matt.ucc.asn.au/dropbear/dropbear.html I strongly advise upgrading any systems where dbclient or dropbearkey is used with arguments/input provided from external sources, or systems where Unix usernames can be chosen arbitrarily. The release also includes a fix for a TCP forwarding issue that has affected quite a few people. Cheers, Matt 2016.74 - 21 July 2016 - Security: Message printout was vulnerable to format string injection. If specific usernames including "%" symbols can be created on a system (validated by getpwnam()) then an attacker could run arbitrary code as root when connecting to Dropbear server. A dbclient user who can control username or host arguments could potentially run arbitrary code as the dbclient user. This could be a problem if scripts or webpages pass untrusted input to the dbclient program. - Security: dropbearconvert import of OpenSSH keys could run arbitrary code as the local dropbearconvert user when parsing malicious key files - Security: dbclient could run arbitrary code as the local dbclient user if particular -m or -c arguments are provided. This could be an issue where dbclient is used in scripts. - Security: dbclient or dropbear server could expose process memory to the running user if compiled with DEBUG_TRACE and running with -v The security issues were reported by an anonymous researcher working with Beyond Security's SecuriTeam Secure Disclosure www.beyondsecurity.com/ssd.html - Fix port forwarding failure when connecting to domains that have both IPv4 and IPv6 addresses. The bug was introduced in 2015.68 - Fix 100% CPU use while waiting for rekey to complete. Thanks to Zhang Hui P for the patch
