Vectra Networks Discovers High Severity Internet Explorer 11 Vulnerability Following Hacking Team Cyber Attack

Vectra Threat Lab Finds Exploitable Use-After-Free Vulnerability that Can Let Attackers Bypass Standard Memory Protections in Popular Web Browser

July 15, 2015

3 Min Read


SAN JOSE, Calif. — July 14, 2015 — Vectra Networks, the leader in real-time detection of in-progress cyber-attacks, today announced that the Vectra Threat Labs discovered a high severity vulnerability in Internet Explorer (IE) 11 last week following the cyber attack on the Italian company known as Hacking Team. Remediation is being announced today in Microsoft’s Security Bulletin, with more information available at

After analyzing the leaked data from last week’s cyber attack on Hacking Team, Vectra researchers identified a previously unknown vulnerability in IE 11 that impacts a fully patched IE 11 web browser on both Windows 7 and Windows 8.1. The vulnerability is an exploitable use-after-free (UAF) vulnerability that occurs within a custom heap in JSCRIPT9. Since it exists within a custom heap, it can allow an attacker to bypass protections found in standard memory.

The hunt for the vulnerability began when Vectra noticed an email from an external researcher who attempted to sell a proof-of-concept exploit to Hacking Team. The email described an exploitable use-after-free bug in IE 11. While Hacking Team declined to buy the PoC, the email gave enough information for Vectra researchers to find and analyze the bug. After approaching Hacking Team, the researcher may have gone elsewhere to sell the bug, and if successful it may have been exploited in the wild.

“While Vectra Threat Labs usually looks into exploits found in our customers’ networks, in this case we became aware of a vulnerability present on a very large number of PCs,” said Oliver Tavakoli, Vectra Networks CTO. “We have been working closely with the Microsoft Security Response Center for the past week to ensure that a patch is available on short notice.”

Vectra Threat Labs’ reports and blogs zero-in on the attacker’s goals, places them in the context of the broader campaign the attacker is waging, and provides insights into durable ways in which threats can be detected and mitigated.

About Vectra Networks
Vectra Networks™ is the leader in real-time detection of in-progress cyber attacks. The company’s automated threat-management solution continuously monitors internal network traffic to pinpoint cyber attacks as they happen. It then automatically correlates threats against hosts that are under attack and provides unique context about what attackers are doing so organizations can quickly prevent or mitigate loss. Vectra prioritizes attacks that pose the greatest business risk, enabling organizations to make rapid decisions on where to focus time and resources. In 2015, Gartner named Vectra a Cool Vendor in Security Intelligence for addressing the challenges of post-breach threat detection. Vectra’s investors include Khosla Ventures, Accel Partners, IA Ventures and AME Cloud Ventures. The company’s headquarters are in San Jose, Calif., and it has European operations in Zurich. More information can be found at


Vectra Networks is a registered trademark of Vectra Networks in the United States and other countries.  All other brands, products, or service names are or may be trademarks or service marks of their respective owners.

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