Feeds

Don't be a DDoS dummy: Patch your NTP servers, plead infosec bods

Popular attack method could be stopped with a config tweak

Providing a secure and efficient Helpdesk

Security researchers have responded to recent denial of service attacks against gaming websites and service providers that rely on insecure Network Time Protocol servers by drawing up a list of vulnerable systems.

Network Time Protocol (NTP) offers a means of synchronising clocks over a computer network. Features of the simple UDP-based protocol mean it is possible to abuse it to return a large reply to a small request.

The technique was used to take down Battle.net, League of Legends, Steam and other gaming sites in late December for reasons that still remain unclear, weeks later.

Symantec recorded a "significant spike in NTP reflection attacks" in general over the Christmas season.

DNS-based reflection and amplification attacks were used in high volume attacks against Spamhaus and others in 2013. "NTP-based attacks use similar techniques, just a different protocol," CloudFlare, the web security firm that helped Spamhaus mitigate last year's packet flood, explains.

Open NTP servers are the new open DNS resolvers. In just the same way that the ‪openresolverproject.org aimed to list open DNS resolvers a new service called openntpproject.org.

The message to web admins and ISPs in both cases is clear: fix your servers and prevent them from participating in amplification attacks. Resolving misconfiguration problems in either case is straightforward and shouldn't take more than a few minutes. In the case of open DNS resolvers the fix involves configuration changes, while open NTP servers can be taken out of the pool of systems open to abuse by cybercrooks through either patching or disabling an abusable service.

Publicly accessible NTP servers can be abused to swamp a target system with UDP traffic. An attacker would send a series of "get monlist" requests to a vulnerable NTP server, with the source address spoofed to be the victim’s.

US-CERT advises sys admins to either disable the monlist functionality within the NTP server or to upgrade to the latest version of the technology (NTP 4.2.7), which doesn't automatically enable the problematic monlist service. A small query can redirect megabytes of traffic, security experts at the SANS Institute's Internet Storm Centre warn.

The Open NTP Project is a useful resource in helping to identify vulnerable systems because it allows sysadmins to use external IP addresses to search through a ready-compiled database of affected machines, as explained in a blog post by cloud security firm Qualys here. ®

New hybrid storage solutions

More from The Register

next story
Google recommends pronounceable passwords
Super Chrome goes into battle with Mr Mxyzptlk
Apple Pay is a tidy payday for Apple with 0.15% cut, sources say
Cupertino slurps 15 cents from every $100 purchase
Infosec geniuses hack a Canon PRINTER and install DOOM
Internet of Stuff securo-cockups strike yet again
Reddit wipes clean leaked celeb nudie pics, tells users to zip it
Now we've had all THAT TRAFFIC, we 'deplore' this theft
YouTube, Amazon and Yahoo! caught in malvertising mess
Cisco says 'Kyle and Stan' attack is spreading through compromised ad networks
TorrentLocker unpicked: Crypto coding shocker defeats extortionists
Lousy XOR opens door into which victims can shove a foot
Greater dev access to iOS 8 will put us AT RISK from HACKERS
Knocking holes in Apple's walled garden could backfire, says securo-chap
prev story

Whitepapers

Providing a secure and efficient Helpdesk
A single remote control platform for user support is be key to providing an efficient helpdesk. Retain full control over the way in which screen and keystroke data is transmitted.
Top 5 reasons to deploy VMware with Tegile
Data demand and the rise of virtualization is challenging IT teams to deliver storage performance, scalability and capacity that can keep up, while maximizing efficiency.
Reg Reader Research: SaaS based Email and Office Productivity Tools
Read this Reg reader report which provides advice and guidance for SMBs towards the use of SaaS based email and Office productivity tools.
Security for virtualized datacentres
Legacy security solutions are inefficient due to the architectural differences between physical and virtual environments.
Secure remote control for conventional and virtual desktops
Balancing user privacy and privileged access, in accordance with compliance frameworks and legislation. Evaluating any potential remote control choice.