Attacks/Breaches
12/30/2013
08:17 PM
Connect Directly
Google+
Twitter
RSS
E-Mail
50%
50%

Attackers Wage Network Time Protocol-Based DDoS Attacks

Yet another protocol being abused for flooding targets with unwanted traffic

Attackers have begun exploiting an oft-forgotten network protocol in a new spin on distributed denial-of-service (DDoS) attacks, as researchers spotted a spike in so-called NTP reflection attacks this month.

The Network Time Protocol, or NTP, syncs time between machines on the network, and runs over port 123 UDP. It's typically configured once by network administrators and often is not updated, according to Symantec, which discovered a major jump in attacks via the protocol over the past few weeks.

"NTP is one of those set-it-and-forget-it protocols that is configured once, and most network administrators don't worry about it after that. Unfortunately, that means it is also not a service that is upgraded often, leaving it vulnerable to these reflection attacks," says Allan Liska, a Symantec researcher in blog post last week.

Attackers appear to be employing NTP for DDoSing similar to the way DNS is being abused in such attacks. They transmit small spoofed packets requesting a large amount of data sent to the DDoS target's IP address. According to Symantec, it's all about abusing the so-called "monlist" command in an older version of NTP. Monlist returns a list of the last 600 hosts that have connected to the server. "For attackers the monlist query is a great reconnaissance tool. For a localized NTP server it can help to build a network profile. However, as a DDoS tool, it is even better because a small query can redirect megabytes worth of traffic," Liska explains in the post.

Monlist modules can be found in NMAP as well as in Metasploit, for example. Metasploit includes monlist DDoS exploit module.

The spike in NTP reflection attacks occurred mainly in mid-December, with close to 15,000 IPs affected, and dropped off significantly after Dec. 23, according to Symantec's data.

Symantec recommends that organizations update their NTP implementations to version 4.2.7, which does not use the monlist command. Another option is to disable access to monlist in older versions of NTP. "By disabling monlist, or upgrading so the command is no longer there, not only are you protecting your network from unwanted reconnaissance, but you are also protecting your network from inadvertently being used in a DDoS attack," Liska says.

Have a comment on this story? Please click "Add Your Comment" below. If you'd like to contact Dark Reading's editors directly, send us a message.

Kelly Jackson Higgins is Executive Editor at DarkReading.com. She is an award-winning veteran technology and business journalist with more than two decades of experience in reporting and editing for various publications, including Network Computing, Secure Enterprise ... View Full Bio

Comment  | 
Print  | 
More Insights
Comments
Newest First  |  Oldest First  |  Threaded View
JohnB831
50%
50%
JohnB831,
User Rank: Apprentice
1/6/2014 | 4:01:19 PM
re: Attackers Wage Network Time Protocol-Based DDoS Attacks
modify /etc/ntp.conf to have the line:

disable monitor
Register for Dark Reading Newsletters
White Papers
Cartoon
Current Issue
Dark Reading, January 2015
To find and fix exploits aimed directly at your business, stop waiting for alerts and become a proactive hunter.
Flash Poll
Video
Slideshows
Twitter Feed
Dark Reading - Bug Report
Bug Report
Enterprise Vulnerabilities
From DHS/US-CERT's National Vulnerability Database
CVE-2013-7402
Published: 2014-12-17
Multiple unspecified vulnerabilities in request.c in c-icap 0.2.x allow remote attackers to cause a denial of service (crash) via a crafted ICAP request.

CVE-2014-5437
Published: 2014-12-17
Multiple cross-site request forgery (CSRF) vulnerabilities in ARRIS Touchstone TG862G/CT Telephony Gateway with firmware 7.6.59S.CT and earlier allow remote attackers to hijack the authentication of administrators for requests that (1) enable remote management via a request to remote_management.php,...

CVE-2014-5438
Published: 2014-12-17
Cross-site scripting (XSS) vulnerability in ARRIS Touchstone TG862G/CT Telephony Gateway with firmware 7.6.59S.CT and earlier allows remote authenticated users to inject arbitrary web script or HTML via the computer_name parameter to connected_devices_computers_edit.php.

CVE-2014-7170
Published: 2014-12-17
Race condition in Puppet Server 0.2.0 allows local users to obtain sensitive information by accessing it in between package installation or upgrade and the start of the service.

CVE-2014-7285
Published: 2014-12-17
The management console on the Symantec Web Gateway (SWG) appliance before 5.2.2 allows remote authenticated users to execute arbitrary OS commands by injecting command strings into unspecified PHP scripts.

Best of the Web
Dark Reading Radio
Archived Dark Reading Radio
Join us Wednesday, Dec. 17 at 1 p.m. Eastern Time to hear what employers are really looking for in a chief information security officer -- it may not be what you think.