Posts Tagged: honeypot


27
Oct 16

Are the Days of “Booter” Services Numbered?

It may soon become easier for Internet service providers to anticipate and block certain types of online assaults launched by Web-based attack-for-hire services known as “booter” or “stresser” services, new research released today suggests.

The findings come from researchers in Germany who’ve been studying patterns that emerge when miscreants attempt to mass-scan the entire Internet looking for systems useful for launching these digital sieges — known as “distributed denial-of-service” or DDoS attacks.

ddosbomb

To understand the significance of their research, it may help to briefly examine how DDoS attacks have evolved. Not long ago, if one wanted to take down large Web site, one had to build and maintain a large robot network, or “botnet,” of hacked computers — which is a fairly time intensive, risky and technical endeavor.

These days, however, even the least sophisticated Internet user can launch relatively large DDoS attacks just by paying a few bucks for a subscription to one of dozens of booter or stresser services, some of which even accept credit cards and PayPal payments.

These Web-based DDoS-for-hire services don’t run on botnets: They generally employ a handful of powerful servers that are rented from some dodgy “bulletproof” hosting provider. The booter service accepts payment and attack instructions via a front end Web site that is hidden behind Cloudflare (a free DDoS protection service).

But the back end of the booter service is where the really interesting stuff happens. Virtually all of the most powerful and effective attack types used by booter services rely on a technique called traffic amplification and reflection, in which the attacker can reflect or “spoof” his traffic from one or more third-party machines toward the intended target.

In this type of assault, the attacker sends a message to a third party, while spoofing the Internet address of the victim. When the third party replies to the message, the reply is sent to the victim — and the reply is much larger than the original message, thereby amplifying the size of the attack.

To find vulnerable systems that can be leveraged this way, booters employ large-scale Internet scanning services that constantly seek to refresh the list of systems that can be used for amplification and reflection attacks. They do this because, as research has shown (PDF), anywhere from 40-50 percent of the amplifiers vanish or are reassigned new Internet addresses after one week.

Enter researchers from Saarland University in Germany, as well as the Yokohama National University and National Institute of Information and Communications Technology — both in Japan. In a years-long project first detailed in 2015, the researchers looked for scanning that appeared to be kicked off by ne’er-do-wells running booter services.

To accomplish this, the research team built a kind of distributed “honeypot” system — which they dubbed “AmpPot” — designed to mimic services known to be vulnerable to amplification attacks, such as DNS and NTP floods.

“To make them attractive to attackers, our honeypots send back legitimate responses,” the researchers wrote in a 2015 paper (PDF). “Attackers, in turn, will abuse these honeypots as amplifiers, which allows us to observe ongoing attacks, their victims, and the DDoS techniques. To prevent damage caused by our honeypots, we limit the response rate. This way, while attackers can still find these ratelimited honeypots, the honeypots stop replying in the face of attacks.”

In that 2015 paper, the researchers said they deployed 21 globally-distributed AmpPot instances, which observed more than 1.5 million attacks between February and May 2015. Analyzing the attacks more closely, they found that more than 96% of the attacks stem from single sources, such as booter services.

“When focusing on amplification DDoS attacks, we find that almost all of them (>96%) are caused by single sources (e.g. booters), and not botnets,” the team concluded. “However, we sadly do not have the numbers to compare this [to] DoS attacks in general.”

Many large-scale Internet scans like the ones the researchers sought to measure are launched by security firms and other researchers, so the team needed a way to differentiate between scans launched by booter services and those conducted for research or other benign purposes.

“To distinguish between scans performed by researchers and scans performed with malicious intent we relied on a simple assumption: That no attack would be based on the results of a scan performed by (ethical) researchers,” said Johannes Krupp, one of the main authors of the report. “In fact, thanks to our methodology, we do not have to make this distinction upfront, but we can rather look at the results and say: ‘We found attacks linked to this scanner, therefore this scanner must have been malicious.’ If a scan was truly performed by benign parties, we will not find attacks linked to it.”

SECRET IDENTIFIERS

What’s new in the paper being released today by students at Saarland University’s Center for IT-Security, Privacy and Accountability (CISPA) is the method by which the researchers were able to link these mass-scans to the very amplification attacks that follow soon after.

The researchers worked out a way to encode a secret identifier into the set of AmpPot honeypots that any subsequent attack will use, which varies per scan source. They then tested to see if the scan infrastructure was also used to actually launch (and not just to prepare) the attacks. Continue reading →


13
Oct 16

IoT Devices as Proxies for Cybercrime

Multiple stories published here over the past few weeks have examined the disruptive power of hacked “Internet of Things” (IoT) devices such as routers, IP cameras and digital video recorders. This post looks at how crooks are using hacked IoT devices as proxies to hide their true location online as they engage in a variety of other types of cybercriminal activity — from frequenting underground forums to credit card and tax refund fraud.

networktechniciansRecently, I heard from a cybersecurity researcher who’d created a virtual “honeypot” environment designed to simulate hackable IoT devices. The source, who asked to remain anonymous, said his honeypot soon began seeing traffic destined for Asus and Linksys routers running default credentials. When he examined what that traffic was designed to do, he found his honeypot systems were being told to download a piece of malware from a destination on the Web.

My source grabbed a copy of the malware, analyzed it, and discovered it had two basic functions: To announce to a set of Internet addresses hard-coded in the malware a registration “I’m here” beacon; and to listen for incoming commands, such as scanning for new vulnerable hosts or running additional malware. He then wrote a script to simulate the hourly “I’m here” beacons, interpret any “download” commands, and then execute the download and “run” commands.

The researcher found that the malware being pushed to his honeypot system was designed to turn his faux infected router into a “SOCKS proxy server,” essentially a host designed to route traffic between a client and a server. Most often, SOCKS proxies are used to anonymize communications because they can help obfuscate the true origin of the client that is using the SOCKS server.

proxy

When he realized how his system was being used, my source fired up several more virtual honeypots, and repeated the process. Employing a custom tool that allows the user to intercept (a.k.a. “man-in-the-middle”) encrypted SSL traffic, the researcher was able to collect the underlying encrypted data passing through his SOCKS servers and decrypt it.

What he observed was that all of the systems were being used for a variety of badness, from proxying Web traffic destined for cybercrime forums to testing stolen credit cards at merchant Web sites. Further study of the malware files and the traffic beacons emanating from the honeypot systems indicated his honeypots were being marketed on a Web-based criminal service that sells access to SOCKS proxies in exchange for Bitcoin.

Unfortunately, this type of criminal proxying is hardly new. Crooks have been using hacked PCs to proxy their traffic for eons. KrebsOnSecurity has featured numerous stories about cybercrime services that sell access to hacked computers as a means of helping thieves anonymize their nefarious activities online. Continue reading →