Comment Digium says: Protocol, not program (Score 3, Informative) 141
So as is unfortunately typical, some of the quotes I made of course been taken out of proportion. My quote was not that "Asterisk attacks are endemic", but that SIP-based brute force attacks are endemic. Every SIP system that is open to the "public" Internet is seeing large numbers of brute-force attacks. Sites that have weak username and weak password control will be compromised - this is little different than email accounts being taken over by password-guessing systems and used for sending floods of email. The significant difference is that when someone takes over a SIP platform to make outbound calls, there is usually a direct monetary cost, which gets people's attention very quickly. I hear reports of these types of attacks now all the time - it's not unusual, and it's not just Asterisk. We had a blog about this a year ago; this is just a re-packaging of the same news a year later, when recently I unsurprisingly said that attacks are no longer even newsworthy because they're so frequent (hence, the term "endemic".) Apparently, not being newsworthy means... it's newsworthy!
This has little to do with Asterisk other than it happens to be the most prevalent SIP-based platform on the Internet currently. It has everything to do with protocol attacks by script kiddies, or more professional attackers. Bad passwords = easy penetration. The upside on this is that it yet again gets the attention of administrators who might not otherwise know that their password of '1234' might be guessed by criminal users.
The bug that was mentioned? Old news. Really, really old news. And really not even that much of a threat for most people the way they have their systems configured even if they haven't upgraded.
Asterisk, Broadsoft, Cisco, Kamailio, OpenSER, FreeSwitch, Avaya - they're all vulnerable to the brute force attacks if adequate network and username/password security is not implemented. There are ways to minimize, if not eliminate these threats with very standard security policies that should be familiar to any network administrator (ACLs, random passphrases, random client usernames, adequate exception logging, and limits on account usage, to name a few.)
Just as an aside, the Digium SwitchVox platform, which is our commercial re-packaging of Asterisk, has as an element of it's GUI a tool that indicates the relative strength of passwords. We'd encourage any other re-packagers or users of Asterisk to implement a similar UI hint that forces good password behavior by users and local admins. It's really not something that can be done in the core of Asterisk; it has to be done by whatever is the layered UI on top of Asterisk for configuration, or just by good policy.
http://blogs.digium.com/2009/03/28/sip-security/
http://blogs.digium.com/2008/12/06/sip-security-and-asterisk/
John Todd - jtodd@digium.com
Digium, Inc.
Asterisk Open Source Community Director