The most popular track session of RSA San Francisco for the past five years was again packed to the rafters.
Skoudis, founder of Counter Hack Challenges and an incident responder for large organisations, kicked off the session at the 2012 RSA conference last week with three of the top security threats and how to defend against them.
DNS as command-and-control
Malware that used DNS as a command-and-control channel was responsible for two large breaches last year in which hundreds of millions of accounts were stolen.
“We've been talking about this for years,” Skoudis said. “But now there are tools that make this easy, and I've seen them used in truly high-scale breaches.”
The method was more difficult to detect and was not often considered a vector by which malware could bypass security structures to steal data. “As long as the internal machine can resolve names through a name server with recursive look-ups on the internet, then it can reach the attacker," he said.
Logging every DNS query to detect the attack is too resource intensive to be considered a means of defence, Skoudis said.
He recommended security professionals try DNSCAT and employ periodic sniffing; and search for anomalous DNS requests characterised by excessively length, for responses with strange names, and for traffic sent to domains pertaining to countries in which the organisation does not normally do business.
SSL slapped down
The digital certificate model “is a problem”, Skoudis told attendees. The troubled system was in the headlines last year with attacks on certificate and registration authorities (CAs, RAs) DigiNotar and Comodo, and was criticised by respected security researchers including Moxie Marlinspike who proposed an alterative model dubbed Convergence.
Authorities were systematically dropped from major web browser certficate lists, raising further questions about how the decision to trust and un-trust authorities is made.
"Take your favourite browser and look at the certificate revocation list,” Skoudis said. “There were a few [revoked certificates] a year ago, but then there were a few more, and more, and more, and more.”
He illustrated several viable attacks that could bypass web browser SSL warning messages that alert users when certificates are untrusted or unsigned.
These included hacking authorities and using them to issue fraudulent certificates, or simply tricking them into doing so.
Attackers could also create fake certificates that have a MD5 hash collision with a trusted certificate, target SSL or Transport Layer Security (TLS) flaws demonstrated by the 2011 BEAST attack, or use web browser validation vulnerabilities.
“Why compromise a CA when there are much easier ways? I think we'll see a proliferation of this in 2012,” Skoudis said, adding that end users can be convinced to disregard web browser SSL warnings and accept cheap unsigned certificates.
Over the next 12 months, Skoudis predicts that more malware will carry certificates and install them on end-user machines in an attempt to evade detection.
“It is the most widely-deployed security protocol in the world, and it secures trillions of dollars in transactions, but sometimes it feels like we are trying to apply bandages to a very leaky dam,” Skoudis said, speaking of the SSL model.
To reduce risk, organisations should upgrade to the latest version of TLS and revise web browser certificate lists. The SANS Internet Storm Centre will this year release a tool capable of automating that process, which will give insight into what certificates are added or dumped by web browsers.
Mobile malware as a network infection vector
The anarchistic Android marketplace had Skoudis worried - not just because individuals were at risk from downloading backdoored counterfeit applications, but because compromised devices posed a significant risk to enterprise networks.
“If I can get you to install a backdoor app, and you join the wireless enterprise network, I can ride in,” Skoudis said. “Many of the VIPs in your organisations may have demanded this kind of access.”
The first step professionals should take to defend against the threat was to develop policy for mobile devices. Lee Neely, a security architect at the US Government's Lawrence Livermore National Labs, last month released an extensive policy document checklist for mobiles and networks which Skoudis recommeded.
“Establish a process for evaluating and approving specific applications for use in mobile environments and analyse the application in a sandbox on the network,” Skoudis said. “And build a secure wireless network that is separate from your internal network.”
Hacktivism is back
Hacktivism was not new, but for Ullrich, the chief research officer at the SANS Institute, it was a serious threat. “What they do is not that skilled, but they are seeking out security vulnerabilities that we all know how to fix,” Ullrich said.
Hacking collectives such as Anonymous and the Anti-Security movement continued to attack organisations using simple exploits that take advantage of “basic mistakes” made by victim organisations.
He said defending against hacktivists required basic security improvements to inventory control, software security, authentication, and monitoring.
“Do you know all the devices you have? Because the one that you forget is the one they will attack. It's not exciting, it's not exciting, but you have to get it done.
“Simple things will significantly improve your security.”
SCADA at home
The popularity of home automation systems is exploding but the technology lacks security. Potential hacks could impact a range of wireless technologies from physical locks on buildings to energy smart meters, and it has Ullrich concerned.
“The technologies focus on cost, not security. [Breaching] home automation means things like opening the front door and turning off the alarms,” he said.
Ullrich points out that home networking equipment often connects to cloud services for functions such as temperature checks without proper authentication.
He said that wardriving using the ZigBee specification popular with the home automation systems would become more popular over the next 12 months.
Researcher Travis Goodspeed developed a portable wardriving ZigBee kit which he used to map sprinker systems in the US, and plans to release the software for the package this year.
Whether it's Amazon, Dropbox, or Google, cloud computing is surging in populairty. But to Ullrich, it represents a security threat. “We saw some real cloud exploits last year,” Ullrich said, citing security incidents at Dropbox and Amazon.
He said that shared hosting environments are becoming “harder to isolate from each other”, a risk that is exacerbated by the trend to put larger quantities of more sensitive data into the cloud.
IPv6: Ullrich points out that he has seen more “accidental” IPv6 deployments where systems were rolled out without being secured. He notes that handheld smartphones and tablets are IPv6 devices.
Oldies: “Just because something is old, doesn't mean it isn't important”, Skoudis said. “Most of you in this room who will get popped this year will be victims to phishing.
Social networking: Criminals realise this is a golden age for social engineering and Skoudis expects them to increasingly plunder networks, pre-empting moves to improve security and privacy.
Malware: The industry needs to move away from an anti-malware and blacklisting model towards whitelisting. “Whitelisting is the soluton in the end,” Ullrich said.
DNSSEC: The Domain Name System Security Extensions will help repair trust, but will not hinder advanced malicious command and control systems.