Researcher shows how to strike back at web assailants

Exploiting the exploiters

A security researcher has disclosed details on more than a dozen previously unknown vulnerabilities that people responding to web-based attacks can exploit to strike back at online assailants.

The bugs reside in off-the-shelf crimeware kits that go by names such as Eleonore, Liberty, Neon, and Yes. Attackers install them on compromised websites to streamline the process of exploiting unpatched vulnerabilities on the PCs of people who visit them.

It has long been known that some of the exploit kits are themselves susceptible to attacks, and on Thursday Laurent Oudot, CEO of French security consultancy Tehtri-Security, detailed 13 bugs that can be exploited to turn the tables on the criminals running the software. They make it possible for law enforcement agents and other investigators of online attacks to destroy command and control servers, identify the miscreants, and in some cases even launch client-side attacks against the intruders.

“The offensive concepts that we've shown today were how to strike back at attackers who use evil web tools like Exploit Packs, Web backdoors, etc.,” Oudot told The Register in an online discussion a few hours after he made a presentation at the SyScan security conference in Singapore. “Basically, we explained that it is possible to create traps or to remotely attack the malicious web tools used by people controlling botnets.”

One of the attacks against Eleonore allows investigators to steal the authentication cookies of miscreants logging in to the administrative panel used to control an attack site. It starts with as SQL-injection exploit through a browser's referrer field to plant strings in the server's database that make the panel vulnerable to XSS, or cross-site scripting exploits. Investigators can then exploit that hole and steal the cookies, which are used to gain administrative access to the panel.

Oudot said his presentation included instructions on carrying out 13 separate exploits. He has not yet published the details but said he would probably do so eventually. A brief description of the talk is towards the bottom of this page, and additional details are here.

The presentation highlights the fine line between investigating and responding to online attacks on the one hand and running afoul of anti-hacking laws on the other. In some countries, mere possession of attack scripts and hacking tools is considered a crime. US law generally prohibits the intrusion onto another person's computer.

“The question is: Are you accessing their machine without authorization or in excess of authorization?” said Mark Rasch, a former assistant US attorney who prosecuted hacking crimes and is the founder of Secure IT experts in Bethesda, Maryland. “If the answer to that question is yes then it's a technical violation of the US computer crimes statutes. In other words, you do so at your own legal peril.” ®