DDoS Botnet Detects Defenses

Tuesday, August 27, 2013 @ 05:08 PM gHale


A new version of a distributed denial-of-service (DDoS) toolkit can now check victims’ networks for DDoS mitigation methods so it can circumvent the defenses.

DirtJumper Drive, a do it yourself kit that makes it easy to create a botnet to DDoS a target, has been evolving over the past year. This summer, the malware started to obfuscate its communique with bots, said researchers at Arbor Networks ASERT team. Now DirtJumper Drive is fighting back against DDoS mitigation services.

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“We found one attack that was searching for DDoS mitigation techniques and trying to actively bypass those so it can get through to its target and get the target down,” said Jason Jones, a security research analyst with Arbor Networks’ ASERT. The attack appeared to be against a financial industry organization, he said.

“This time, they are definitely going after us and others in the DDoS mitigation space. I want to make sure we share enough information, samples and future [ways] to identify it … It’s definitely a step up in the protection game for us,” he said.

It also points to what security researchers have been saying over the past couple of years, the sophistication level of the bad guys keeps increasing.

“Historically, DDoS malware has not been as sophisticated as other malware and not as advanced,” Jones said. “It will be harder to detect.”

DirtJumper, created by a Russian-speaking malware writer known as “sokol,” can cost as little as $150 in the underground, according to DDoS mitigation provider Prolexic.

The new version discovered by Arbor’s ASERT team has three other attacks in addition to the “smart” attack that sniffs out and bypasses DDoS defenses. Among those features are an ICMP attack and an attack that extends the amount of time a connection stays open. The “smart” attack module detects and cheats anti-DDoS cookies, redirection methods, and metatags used for redirecting malicious IP traffic. Jones said Arbor is countering the new botnet feature with special rules for DirtJumper Drive that prevents it from getting past its mitigation services.

The attack basically looks for a “Set-Cookie” or a “Location” header and “will parse out either the Cookie value or new URL location use those values in the next packet it sends. It will also look for a meta equiv refreshtag, location= or document.location.href inside of the response from the server,” Jones wrote in a blog post about the attacks. “This is one of, if not the, first pieces of DDoS malware that ASERT has seen actively attempt to defeat known mitigation techniques.”

DDoS attacks can be a financial nightmare. A 24-hour outage due to a DDoS can result in a loss of around $27 million, or $2.1 million for a four-hour website outage, according to Forrester Research. Financial services firms lost $17 million per DDoS attack last year, Forrester estimates.

Dell SecureWorks, which said it is seeing hacktivists employing other methods in addition to DDoS, recommends employing a bogus IP address block list at the network perimeter to keep DDoS IP traffic out. Separating critical services such as HTTP, FTP, and DNS, and setting up a dedicated firewall for each and running load-balancers can help as well, the company said.

“Evaluate and implement dedicated DDoS mitigation technologies. Having dedicated hardware for mitigating DDoS and DoS-styled attacks can help keep strain off targeted systems and provide your DDoS response team with much needed time to find and eliminate the attack,” according to a Dell SecureWorks advisory.



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