Qakbot Attackers Remain Alive and Quacking, Researchers Find

Cyber Security Threat Summary:
The commonality among "bank transfer request[.]lnk," "invoice OTP bank[.]pdf[.]lnk," and "URGENT-Invoice-27-August[.]docx[.]lnk" is that they are all names of Windows shortcut files found in Zip archives attached to phishing emails, as reported by Cisco Talos researchers. This malicious activity continues despite the "Operation Duck Hunt" law enforcement effort, which disrupted a significant portion of the Qakbot botnet infrastructure in late August, leading to the seizure of servers and cryptocurrency worth nearly $9 million and the removal of Qakbot from 700,000 endpoints.

According to Talos researchers, the phishing campaign they are monitoring commenced before the takedown and has persisted since. This indicates that the law enforcement action may have primarily affected Qakbot's command-and-control servers, leaving the spam delivery infrastructure intact. Despite the disruption, various security experts cautioned that the operation primarily targeted infrastructure. The individuals leading the operation and their employed developers remain unapprehended and could potentially rebuild the compromised segments of this profitable operation.

Cisco Talos has attributed the ongoing phishing campaign to Qakbot based on the metadata found in the latest malicious files. These files appear to have been generated on the same machine as previous campaigns conducted by the group. Researchers have identified a commonality among these malicious files, as they all contain metadata indicating a hard drive with the serial number "0x2848e8a8."

In this particular phishing campaign, the attached Zip archives contain link files that are designed to load an Excel add-in extension, known as a .xll file. These files are used to install the Remcos backdoor, which provides persistent remote access to an endpoint. Additionally, researchers have discovered that the link files execute a Powershell script intended to download an executable from a remote IP address, which in turn installs the ransomware known as Ransom Knight, also referred to as Knight ransomware.

Security Officer Comments:
Cisco Talos speculates that Qakbot, or someone affiliated with Qakbot, may act as an affiliate of the Knight ransomware operation, rather than directly overseeing it. The question of whether Qakbot will resurrect its botnet infrastructure to distribute malware and exert remote control through its command-and-control servers remains uncertain. Qakbot, initially emerging as a banking Trojan in 2008, was among the world's longest-standing botnets. Over the years, with numerous updates, it was linked to substantial financial losses, totaling hundreds of millions of dollars, as confirmed by senior FBI and Justice Department officials.

Suggested Correction(s):

Users should always be cautious of individuals or organizations that ask for personal information. Most companies will not ask for sensitive data from its customers. If in doubt, users should verify with the company itself to avoid any potential issues.

Users should always take a close look at the sender’s display name when checking the legitimacy of an email. Most companies use a single domain for their URLs and emails, so a message that originates from a different domain is a red flag.

As a general rule, users should not click links or download files even if they come from seemingly “trustworthy” sources.

Check for mismatched URLs. While an embedded URL might seem perfectly valid, hovering above it might show a different web address. In fact, users should avoid clicking links in emails unless they are certain that it is a legitimate link.

Users should always be on the lookout for any grammatical errors and spelling mistakes. Legitimate companies will often employ proofreaders and editors who ensure that the materials they send out are error-free.

Users should not be frightened or intimidated by messages that have an alarmist tone. They should double check with the company if they are uncertain about the status of their accounts.

Phishing emails are designed to be sent to a large number of people, so they need to be as impersonal as possible. Users should check whether the message contains a generic subject and greeting, as this can be a sign of a phishing attempt.

Although not every end user has access to advanced anti-phishing software, they can still use the built-in protection of their email clients to filter messages. One example is setting the email client to block all images unless approved.

Legitimate companies will never send confirmation emails unless there are specific reasons for doing so. In fact, most companies will avoid sending unsolicited messages unless it’s for company updates, newsletters, or advertising purposes.

Users should always take the context of an email or message into account. For example, most online accounts do away with viewable member numbers, so users should be wary if they receive emails containing a “member number” for services that generally don’t use them.

It is important to take note of unusual information in the text of the message. Any mentions of operating systems and software that are not typically used by consumers can often be indicators of a phishing attempt.

If it seems suspicious, it probably is. Users should always err on the side of caution when it comes to sending out personally identifiable information through messages and emails.