Security Experts:

Connect with us

Hi, what are you looking for?


Malware & Threats

CryptoWall 2.0 Ransomware Capable of Executing 64-Bit Code: Cisco

Researchers of Cisco’s Talos Group have conducted an in-depth analysis of CryptoWall 2.0, a notorious piece of ransomware designed to encrypt files on infected systems and hold them for ransom.

Researchers of Cisco’s Talos Group have conducted an in-depth analysis of CryptoWall 2.0, a notorious piece of ransomware designed to encrypt files on infected systems and hold them for ransom.

CryptoWall has been around since at least November 2013. The malware has been distributed through spam and malvertising campaigns. Exploits kits such as Flashpack, Angler, Infinity and RIG have been used to push the threat onto victims’ computers.

In August 2014, the Dell SecureWorks Counter Threat Unit reported that CryptoWall had infected nearly 625,000 systems between mid-March and August 24, encrypting over 5 billion files. Researchers determined that the ransomware had helped its masters earn more than $1 million in the six-month period.

The first samples of CryptoWall 2.0 were spotted by researchers in October. Experts noted at the time that the malware authors had started using the Tor anonymity network to protect command and control (C&C) traffic.

According to Cisco, the CryptoWall 2.0 dropper relies on multiple exploits for initial access to a system. One of the samples analyzed by researchers exploited an old Windows vulnerability (CVE-2013-3660) to escalate its privileges.

In order to ensure that it’s not executed in a sandbox environment, the ransomware incorporates anti-VM and anti-emulation checks that must be passed before the actual malware is installed on a system. Both the dropper and the binary it downloads are protected by several layers of encryption, Cisco said.

Experts noted that CryptoWall 2.0 creates registry entries for persistence, and disables system protections and various services (Windows Update, ERSvc, Security Center, Windows Defender, Background Intelligent Transfer Service, Windows Error Reporting Service) on the infected device.

An interesting aspect of CryptoWall 2.0 is that it can run 64-bit code directly from the 32-bit dropper. It does this by leveraging the WoW64 (Windows 32-bit on Windows 64-bit) subsystem to switch the processor execution context.

“[The analyzed sample] includes some 64 bit code (and an exploit DLL) directly in its main 32-bit executable. Although the main module is running in 32-bit mode, it is capable of executing all the 64-bit functions it needs. It accomplishes this by performing a direct Processor execution context switch,” Cisco researchers explained in a blog post.

CryptoWall has taken the place of CryptoLocker, the most notorious piece of ransomware before its infrastructure was disrupted by law enforcement authorities last summer as part of an operation targeting the Gameover Zeus malware. While the original CryptoLocker is out of the picture, cybercriminals still leverage its reputation. In mid-December, Barracuda Labs researchers reported spotting infections with a ransomware claiming to be CryptoLocker in Australia.

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

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

Malware & Threats

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


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

Malware & Threats

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