Cybercriminals and threat actors often use tried-and-tested vulnerabilities in order to infect user systems and consequently, penetrate an enterprise network. This highlights the importance of patching systems and keeping software and applications up-to-date.

We recently spotted DYREZA malware leveraging an old vulnerability found existing in Adobe Reader and Acrobat and covered under CVE-2013-2729. Accordingly, once this vulnerability is successfully exploited it could lead to the execution of arbitrary code on the affected system.

Figures 1-2. Screenshots of spam emails

DYREZA malware uses spammed message that purports to be an invoice notification as its infection vector. It has a malicious .PDF file attachment, detected by Trend Micro as TROJ_PIDIEF.YYJU. When executed, it exploits the CVE-2013-2729 vulnerability, which leads to the download of TSPY_DYRE.EKW, a variant of DYREZA (also known as DYRE and DYRANGES).

DYREZA is a malware known for stealing banking credentials and associated with parcel mule scams. We recently wrote a blog post detailing the role that this malware plays in the threat landscape ecosystem and some of its notable behavior, including its capability to perform man-in-the-middle (MITM) attacks via browser injections, monitoring online banking sessions of targeted banks, and stealing other information such as browser versions, snapshots, and personal certificates.

Users and enterprises are at risk since DYREZA can get other types of data such as personal identifiable information (PII) and credentials via browser snapshots. Aside from this, we also reported that the CUTWAIL botnet leads to the download of both UPATRE and DYRE malware.

What makes TSPY_DYRE.EKW notable is its ability to steal crucial information via injecting malicious codes onto certain banking and bitcoin login webpages. Some of the bitcoin pages it monitors are:

bitbargain.co.uk/*

bitbargain.co.uk/login*

bitpay.com/*

bitpay.com/merchant-login*

localbitcoins.com/*

localbitcoins.com/accounts/login*

www.bitstamp.net/*

www.bitstamp.net/account/login*

Apart from its information stealing routines, TSPY_DYRE.EKW has the capability to connect to certain malicious websites to send and receive information. Moreover, it can connect to specific STUN (Session Traversal Utilities for NAT) servers to determine the public IP address of the compromised computer. As such, cybercriminals can find out the location of the malware or possibly determine the affected users’ and organizations’ locations. The top country victims are Ireland, United States, Canada, Great Britain, and Netherlands.

Bitcoin is a digital currency that has real world value. Cybercriminals often go after bitcoins since it presents a new venue for them to generate profit. While this is not the first instance that scammers and cybercriminals target bitcoins, this new attack highlights how traditional threats like exploits and banking malware remain to be a relevant means for cybercriminals to steal both user credentials and hit a relatively new platform – bitcoins. It also teaches us an important lesson about keeping systems and software applications updated to its latest version.

Trend Micro protects users from this threat via its Smart Protection Network that detects the spammed message and all related malware.

With additional analysis from Rhena Inocencio, Karla Agregada, and Michael Casayuran