Feeds

New DNS trojan taints entire LAN from single box

One 'sploit pwns all

The Power of One eBook: Top reasons to choose HP BladeSystem

Internet security experts are warning of a new rash of malware attacks that can hijack the security settings of a wide variety of devices on a local area network, even when they are hardened or don't run on Windows operating systems.

Once activated, the trojan sets up a rogue DHCP, or dynamic host configuration protocol, server on the host machine. From there, other devices using the same LAN are tricked into using a malicious domain name system server, instead of the one set up by the network administrator. The rogue DNS server sends the devices to fraudulent websites that in many cases can be hard to identify as impostors.

A new variant of Trojan.Flush.M is making the rounds, Johannes Ullrich, CTO of the SANS Internet Storm Center warns here. It offers several improvements over its predecessor, which was discovered in early December. Among other changes, the new strain no longer specifies a DNS domain name, making the rogue DHCP server harder to detect.

"This kind of malware is definitely dangerous because it affects systems that themselves are not vulnerable" to the trojan, Ullrich told The Register. "So all you need is one system infected in the network and it will affect a lot of other nonvulnerable systems."

Of course, one way to thwart the attack is to hardwire DNS server settings into your iPhone, computer or other net-connecting device. This will direct it to bypass the rogue DNS server even if the device is unfortunate enough to get its internet connection from the impostor DHCP server.

Such countermeasures are impractical for networks with thousands of machines, so Ullrich recommends administrators monitor connections to all DNS servers other then the one that's approved for the network. A third choice is to blacklist 64.86.133.51 and 63.243.173.162, which are the DNS servers used by the most recent variant. This is the least effective measure, since future variants will surely tap new IP addresses. ®

Designing a Defense for Mobile Applications

More from The Register

next story
How long is too long to wait for a security fix?
Synology finally patches OpenSSL bugs in Trevor's NAS
Don't look, Snowden: Security biz chases Tails with zero-day flaws alert
Exodus vows not to sell secrets of whistleblower's favorite OS
Roll out the welcome mat to hackers and crackers
Security chap pens guide to bug bounty programs that won't fail like Yahoo!'s
HIDDEN packet sniffer spy tech in MILLIONS of iPhones, iPads – expert
Don't panic though – Apple's backdoor is not wide open to all, guru tells us
Researcher sat on critical IE bugs for THREE YEARS
VUPEN waited for Pwn2Own cash while IE's sandbox leaked
Four fake Google haxbots hit YOUR WEBSITE every day
Goog the perfect ruse to slip into SEO orfice
Putin: Crack Tor for me and I'll make you a MILLIONAIRE
Russian Interior Ministry offers big pile o' roubles for busting pro-privacy browser
prev story

Whitepapers

Designing a Defense for Mobile Applications
Learn about the various considerations for defending mobile applications - from the application architecture itself to the myriad testing technologies.
Implementing global e-invoicing with guaranteed legal certainty
Explaining the role local tax compliance plays in successful supply chain management and e-business and how leading global brands are addressing this.
Top 8 considerations to enable and simplify mobility
In this whitepaper learn how to successfully add mobile capabilities simply and cost effectively.
Seven Steps to Software Security
Seven practical steps you can begin to take today to secure your applications and prevent the damages a successful cyber-attack can cause.
Boost IT visibility and business value
How building a great service catalog relieves pressure points and demonstrates the value of IT service management.