Security Experts:

Connect with us

Hi, what are you looking for?


Malware & Threats

Angler Exploit Kit Bypasses Microsoft EMET

Angler, currently considered the most sophisticated and most successful exploit kit, has been observed delivering Flash and Silverlight exploits capable of evading Microsoft’s Enhanced Mitigation Experience Toolkit (EMET).

Angler, currently considered the most sophisticated and most successful exploit kit, has been observed delivering Flash and Silverlight exploits capable of evading Microsoft’s Enhanced Mitigation Experience Toolkit (EMET).

Microsoft EMET is a tool designed to make it more difficult, expensive and time consuming for attackers to exploit vulnerabilities on Windows systems. However, researchers have disclosed methods that can be used to bypass EMET protections on numerous occasions and malicious actors have now also found ways to evade the security tool.

According to FireEye researchers, the Flash Player and Microsoft Silverlight exploits currently leveraged by Angler to deliver malware don’t rely on typical return-oriented programming (ROP) exploit techniques to evade the data execution prevention (DEP) mitigation.

Instead, they leverage the routines built into the Flash Player plugin component Flash.ocx and the Silverlight component Coreclr.dll to call the VirtualProtect and VirtualAlloc memory management functions. This allows the exploits to bypass both DEP and return address validation-based heuristics before executing shellcode.

“Since return address validation heuristics are evaded by utilizing these inbuilt functions from within ActionScript and Silverlight Engine, ROP checks by EMET’s DEP capability are not effective,” FireEye researchers explained.

Experts discovered that the Flash and Silverlight exploits used by Angler can also bypass EMET’s Address Table Filtering (EAF) and EAF+ mitigations.

In the attacks analyzed by FireEye, cybercriminals used these mitigation bypasses to deliver TeslaCrypt ransomware. The security firm pointed out that it has seen successful attacks against Windows 7 running EMET 5.5, which is the latest version of the tool.

“Although there are no quick solutions for the DEP, EAF, and EAF+ evasion techniques, organizations can mitigate this threat through a robust vulnerability management program for end user systems, which includes the installation of security updates for third party software,” researchers said.

Microsoft usually attempts to patch EMET bypasses in new releases of the tool – it will remain to be seen how long it takes the company to neutralize these Angler attacks. A Microsoft spokesperson told SecurityWeek that the company’s free security software “detects and helps remove malware, including Angler.”

In February, FireEye disclosed a method that attackers could use to disable EMET protections by leveraging one of the tool’s own functions. The issue was made public only after Microsoft addressed the vulnerability with the release of EMET 5.5.

*Updated with comment from Microsoft

Related Reading: Blackhole Exploit Kit Author Sentenced to Prison

Related Reading: Nuclear Exploit Kit Creators Make $100,000 Per Month

Written By

Eduard Kovacs (@EduardKovacs) is a contributing editor at SecurityWeek. He worked as a high school IT teacher for two years before starting a career in journalism as Softpedia’s security news reporter. Eduard holds a bachelor’s degree in industrial informatics and a master’s degree in computer techniques applied in electrical engineering.

Click to comment

Daily Briefing Newsletter

Subscribe to the SecurityWeek Email Briefing to stay informed on the latest threats, trends, and technology, along with insightful columns from industry experts.

Join this webinar to learn best practices that organizations can use to improve both their resilience to new threats and their response times to incidents.


Join this live webinar as we explore the potential security threats that can arise when third parties are granted access to a sensitive data or systems.


Expert Insights

Related Content


The changing nature of what we still generally call ransomware will continue through 2023, driven by three primary conditions.


No one combatting cybercrime knows everything, but everyone in the battle has some intelligence to contribute to the larger knowledge base.


A recently disclosed vBulletin vulnerability, which had a zero-day status for roughly two days last week, was exploited in a hacker attack targeting the...

Malware & Threats

Threat actors are increasingly abusing Microsoft OneNote documents to deliver malware in both targeted and spray-and-pray campaigns.

Malware & Threats

A vulnerability affecting IBM’s Aspera Faspex file transfer solution, tracked as CVE-2022-47986, has been exploited in attacks.

Malware & Threats

Microsoft plans to improve the protection of Office users by blocking XLL add-ins from the internet.

Malware & Threats

Unpatched and unprotected VMware ESXi servers worldwide have been targeted in a ransomware attack exploiting a vulnerability patched in 2021.


More than 3,800 servers around the world have been compromised in recent ESXiArgs ransomware attacks, which also include an improved process.