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Researchers have discovered a new version of the DNS Messenger attack which masquerades as the US Securities and Exchange Commission (SEC) and hosts malware on compromised governing administration servers.

On Wednesday, stability researches from Cisco Talos revealed the final results of an investigation into DNS Messenger, a fileless attack which takes advantage of DNS queries to force malicious PowerShell commands on compromised pcs.

A new version of this attack, which the workforce say is “highly qualified in nature,” now attempts to compromise sufferer units by pretending to be the SEC Electronic Data Collecting Evaluation, and Retrieval (EDGAR) system — lately at the heart of a data breach connected to financial fraud — in specifically crafted phishing electronic mail strategies.

These spoofed email messages built them look respectable, but should really a sufferer open up them and download a malicious attachment contained in just, a “multi-stage an infection process” begins.

The malicious attachments utilized in this marketing campaign are Microsoft Term paperwork. However, instead than working with macros or OLE objects to gain a foothold into a system, the threat actors utilized a less common process of an infection, Dynamic Data Exchange (DDE), to perform code execution and set up a distant obtain Trojan (RAT).

It is critical to notice that Microsoft says that DDE is not an exploitable concern, but instead a function “by design,” and will not be taken off.

Talos disagrees, and statements that the workforce has witnessed DDE “actively remaining utilized by attackers in the wild, as demonstrated in this attack.”

In accordance to Talos, the newest malware marketing campaign is very similar to its past evolution. The an infection process takes advantage of DNS TXT data to build a bidirectional command-and-command (C2) channel, in which attackers are capable to interact with the Windows Command Processor working with the contents of DNS TXT history queries and responses created from the threat actor’s DNS server.

When opened, consumers are questioned to allow external hyperlinks to be retrieved. Should really they concur, the malicious document reaches out to an attacker-managed command-and-command (C&C) server which executes the first malware an infection.

This malware was originally hosted on a Louisiana condition governing administration web site, “seemingly compromised and utilized for this goal,” according to the workforce.

PowerShell commands then come into play. Code is retrieved, obfuscated, and then executed, which kicks off persistence on units, registry rewrites, scheduled job creation, and DNS requests are built.

“In this particular case, the malware showcased the ability to leverage WMI, Ads, scheduled responsibilities, as properly as registry keys to acquire persistence,” the scientists notice. “The use of DNS as a conveyance for afterwards stage code and C2 communications is also starting to be extra and extra commonplace.”

Even though the workforce was unable to acquire the upcoming stage of PowerShell code from the C2 servers, Talos says it is possible that communications are limited to stop stability scientists from remaining capable to track the workforce and their methods additional, creating it extra possible that their DNS-based attacks can fly underneath the radar for for a longer period intervals.

However, according to researcher Anthony Yates, he was capable to safe the closing payload by examining some of the conclusions.

Yates says that the payload is regular C&C bot code, and involves data accumulating commands — suggesting the goal of the DNS attack is for cyberespionage.

“Attackers typically use multiple levels of obfuscation in an try to make evaluation extra complicated, evade detection and avoidance capabilities, and carry on to run underneath the radar by restricting their attacks to only the organizations that they are focusing on,” Talos says. “It is also critical for organizations to be knowledgeable of some of the extra appealing methods that malware is working with to execute malicious code on units and gain persistence on units at the time they are infected.”

ZDNet has attained out to Cisco for extra data and will update if we hear again.

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