Shadow Brokers' Tools Pose Zero-Day Risks, Cisco and Fortinet Warn

The Equation Group breach now appears to be very real, as tools emerge that have vendors scrambling.

Shadow Brokers, zero day risk

When news of an alleged breach of the National Security Agency-backed Equation Group first surfaced , there was much speculation about whether the sale by Shadow Brokers of pilfered tools was real or a hoax. As it turns out, multiple security vendors are now confirming that at least some of the tools the Shadow Brokers are selling are real, with critical zero-day vulnerabilities now being exposed in the process.

Among the tools exposed in the first batch that Shadow Brokers made available are two with somewhat interesting and unique names: EPICBANANAS and EXTRABACON. The tools are designed to circumvent network security devices, including firewalls, from multiple vendors in an attempt to give an attacker access to a target network.

Networking giant Cisco is among the targeted vendors and has confirmed that the two attack tools represent real risks of its Cisco ASA and PIX firewall products. The EXTRABACON exploit is being labeled CVE-2016-6366 and is a Simple Network Management Protocol (SNMP) remote code execution vulnerability.

"The EXTRABACON exploit targets a buffer overflow vulnerability in the SNMP code of the Cisco ASA, Cisco PIX and Cisco Firewall Services Module," Omar Santos, principal engineer of Cisco's Product Security Incident Response Team (PSIRT), wrote in a blog post. "An attacker could exploit this vulnerability by sending crafted SNMP packets to an affected Cisco product."

Santos also provides command-line details of how the exploit works against the ASA. The EXTRABACON tool affects all versions of ASA software, and Cisco has now released intrusion-prevention System (IPS) rules that can detect the issue. The clarity and detail that the Cisco PSIRT post provides is part of an effort the company announced in October 2015 to provide its customers with as much transparency and information as possible on Cisco vulnerabilities.

The other critical issue uncovered by the Shadow Brokers sale is the EPICBANANA vulnerability, which now also is identified as CVE-2016-6367 and is an arbitrary code execution vulnerability in the command-line interface (CLI). Santos explained that the way EPICBANANA works is it connects to a targeted device by way of Secure Shell (SSH) or Telnet.

"The attacker must source the attack from an IP address that is allowed by the SSH or telnet commands in the Cisco ASA," Santos wrote. "This is why it is a best practice to only allow SSH or telnet connections from trusted sources and on certain interfaces only (such as the management interface)."

The exploits don't just affect Cisco. Network security vendor Fortinet has also issued an advisory for its FortiGates firmeware (FOS) to defend against the risk from tools exposed by the Shadow Brokers. In the Fortinet case, though, the advisory is currently limited to Fortigate firmware released before 2012.

Going a step further in helping confirm the validity of the Shadow Brokers' claims is the fact that Kaspersky Lab, the security group that first publicly identified the Equation Group, is now also seeing a connection. Initially, when the Shadow Brokers announced that they had breached the Equation Group, Kaspersky Lab had only publicly commented that it was investigating the claims. That investigation now points to solid links with the research that Kaspersky Labs itself had conducted regarding the Equation Group back in February 2015.

"While we cannot surmise the attacker's identity or motivation nor where or how this pilfered trove came to be, we can state that several hundred tools from the leak share a strong connection with our previous findings from the Equation group," a Kaspersky Lab Global Research and Analysis Team (GReAT) report stated.

Sean Michael Kerner is a senior editor at eWEEK and Follow him on Twitter @TechJournalist.

Sean Michael Kerner

Sean Michael Kerner

Sean Michael Kerner is an Internet consultant, strategist, and contributor to several leading IT business web sites.