Dark Reading is part of the Informa Tech Division of Informa PLC

This site is operated by a business or businesses owned by Informa PLC and all copyright resides with them.Informa PLC's registered office is 5 Howick Place, London SW1P 1WG. Registered in England and Wales. Number 8860726.

ABTV //

DDoS

3/1/2018
08:05 AM
Larry Loeb
Larry Loeb
Larry Loeb
50%
50%

Memcache Servers Being Used to Launch Massive DDoS Attacks

Several reports over the last few days are finding that someone is using Memcache servers to launch massive DDoS attacks.\r\n\r\n

A new kind of Distributed Denial of Service (DDoS) has hit the Internet, with amplification parameters that have never been seen before by security experts.

This new attack uses Memcache as an enabler. Memcache is an open source distributed memory caching system that is in wide use to keep web pages available. It excels at working with a large number of open connections.

Memcached servers communicate through TCP or UDP on port 11211.

While the attacks have grown over the last few days, Cloudfare was the first to post an analysis of what was going on.

The DDoS attack proceeds as most do. First, a threat actor sends a request to a vulnerable server with a spoofed IP request as the originator. The request is directed at another IP address which is the true target of the attack. It gets many responses from the server or servers involved in the attack. These will then overwhelm the network that is attached to the server.

In this case, the attackers are using amplification, which means that the response packets are larger than the request packets sent to the vulnerable server.

Cloudfare notes that Memcache-based reflection DDoS attacks can have amplification factors up to 51,200. This is widely higher than the ten or 50 factor that have been previously routine. What has been observed is that attackers sent 15-byte packets to start things off and then the Memcache servers responded with 750kB-packets in return.

Qihoo 360's Network Security Research Laboratory (Netlab) from China confirms this activity. It notes that "UDP reflection and amplification flood attacks continue to lead in last days, making up nearly 70% of total attacks in our observation.

Arbor Networks writes in a blog that it has seen attacks at 500Gbps levels. The majority of servers that were used in the current attacks were in the US and Europe, according to the post.


The fundamentals of network security are being redefined -- don't get left in the dark by a DDoS attack! Join us in Austin from May 14-16 at the fifth-annual Big Communications Event. There's still time to register and communications service providers get in free!

Second Life -- a virtual reality gaming service based in San Francisco -- told its subscribers on Tuesday, February 27, that it "has never seen an attack like this before" in the ten years that it has been operational.

Arbor researchers think that the growth in these specific kinds of attacks is due to it emerging from manual use by skilled attackers, and the use of this vector by "booter/stresser" DDoS-for-hire botnets. They think that the new attack vector was weaponized and broadly leveraged by many attackers within a relatively short interval.

Mitigation will require Memcache users to disable the UDP support that is enabled by default. Many users may not even realize that UDP is on, which is part of the problem. Blocking port 11211 is another action that will stop the server's use as a reflector for these attacks.

Not only that, these servers may not be firewalled and thus directly exposed to the net. A Shodan scan shows 88,000 servers in this condition. Firewalls should be strongly considered for routine use to prevent these and other attacks.

Memcache users need to be a proactive part of this solution to avoid the entire net suffering from malicious DDoS miscreants.

Related posts:

— Larry Loeb has written for many of the last century's major "dead tree" computer magazines, having been, among other things, a consulting editor for BYTE magazine and senior editor for the launch of WebWeek.

Comment  | 
Print  | 
More Insights
Comments
Newest First  |  Oldest First  |  Threaded View
COVID-19: Latest Security News & Commentary
Dark Reading Staff 7/9/2020
4 Security Tips as the July 15 Tax-Day Extension Draws Near
Shane Buckley, President & Chief Operating Officer, Gigamon,  7/10/2020
Russian Cyber Gang 'Cosmic Lynx' Focuses on Email Fraud
Kelly Sheridan, Staff Editor, Dark Reading,  7/7/2020
Register for Dark Reading Newsletters
White Papers
Video
Cartoon
Current Issue
Special Report: Computing's New Normal, a Dark Reading Perspective
This special report examines how IT security organizations have adapted to the "new normal" of computing and what the long-term effects will be. Read it and get a unique set of perspectives on issues ranging from new threats & vulnerabilities as a result of remote working to how enterprise security strategy will be affected long term.
Flash Poll
The Threat from the Internetand What Your Organization Can Do About It
The Threat from the Internetand What Your Organization Can Do About It
This report describes some of the latest attacks and threats emanating from the Internet, as well as advice and tips on how your organization can mitigate those threats before they affect your business. Download it today!
Twitter Feed
Dark Reading - Bug Report
Bug Report
Enterprise Vulnerabilities
From DHS/US-CERT's National Vulnerability Database
CVE-2020-15105
PUBLISHED: 2020-07-10
Django Two-Factor Authentication before 1.12, stores the user's password in clear text in the user session (base64-encoded). The password is stored in the session when the user submits their username and password, and is removed once they complete authentication by entering a two-factor authenticati...
CVE-2020-11061
PUBLISHED: 2020-07-10
In Bareos Director less than or equal to 16.2.10, 17.2.9, 18.2.8, and 19.2.7, a heap overflow allows a malicious client to corrupt the director's memory via oversized digest strings sent during initialization of a verify job. Disabling verify jobs mitigates the problem. This issue is also patched in...
CVE-2020-4042
PUBLISHED: 2020-07-10
Bareos before version 19.2.8 and earlier allows a malicious client to communicate with the director without knowledge of the shared secret if the director allows client initiated connection and connects to the client itself. The malicious client can replay the Bareos director's cram-md5 challenge to...
CVE-2020-11081
PUBLISHED: 2020-07-10
osquery before version 4.4.0 enables a priviledge escalation vulnerability. If a Window system is configured with a PATH that contains a user-writable directory then a local user may write a zlib1.dll DLL, which osquery will attempt to load. Since osquery runs with elevated privileges this enables l...
CVE-2020-6114
PUBLISHED: 2020-07-10
An exploitable SQL injection vulnerability exists in the Admin Reports functionality of Glacies IceHRM v26.6.0.OS (Commit bb274de1751ffb9d09482fd2538f9950a94c510a) . A specially crafted HTTP request can cause SQL injection. An attacker can make an authenticated HTTP request to trigger this vulnerabi...