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Showing posts with label GrayBravo Threat Actor. Show all posts

New ClickFix Campaign Uses Nslookup to Fetch Malicious PowerShell Script


 

According to Microsoft, the ClickFix social engineering technique has evolved in a refined manner, emphasizing that even the most common software applications can be repurposed into covert channels for malware distribution. Using this latest iteration, hackers are no longer only relying on deceptive downloads and embedded scripts to spread malware. 

Through carefully staged prompts, they manipulate victims' trust by instructing them to execute what appears to be harmless system commands. Under this veneer of legitimacy, the command initiates a DNS query via nslookup, quietly retrieving the next-stage payload from attacker-controlled infrastructure. 

By embedding malicious intent within routine administrative behaviors, the campaign transforms a standard troubleshooting tool into an unassuming channel of infection. In Microsoft's analysis, the newly observed campaign instructs victims to use an nslookup command to query a DNS server controlled by the attacker, rather than the system's configured resolver, as directed by the attacker. 

It is designed to request a specific hostname from a remote IP address controlled by the threat actor and forward the query to that address. Instead of returning a regular DNS record, the server responds with a crafted DNS entry with a second PowerShell command embedded in the "Name" field. 

In addition, the Windows command interpreter parses and executes that response, thereby converting a standard DNS query into a covert staging mechanism for code delivery. According to Microsoft Threat Intelligence, this strategy represents another evolution of ClickFix's evasion strategy. 

While earlier versions primarily utilized HTTP-based payload retrieval, this version relies on DNS for both communication and dynamic payload distribution. In spite of the unclear lure used to persuade users, victims are reportedly instructed to execute the command through Windows Run, strengthening the tactic's dependency on social engineering rather than exploits. 

By moving execution to user-initiated system utilities, attackers are reducing the probability that conventional web or network filtering controls will be triggered. PowerShell scripts that are executed in this stage retrieve additional components from infrastructure under attacker control. 

As a result of Microsoft's investigation, it has been determined that the subsequent payload consists of a compressed archive containing a portable Python runtime along with malicious scripts. Prior to establishing persistence on the infected host, these scripts conduct reconnaissance against the host and its domain environment, gathering network and system information. 

In this method, the user creates a VBScript file in their AppData directory, and a shortcut is placed in their Windows Startup folder to ensure execution upon logon. A remote access trojan named ModeloRAT is deployed as part of the infection chain, granting the operator sustained control over compromised systems.

A DNS-based staging strategy allows adversaries to adjust payloads in real time while blending malicious traffic with routine name resolution activity by embedding executable instructions within DNS responses. As well as complicating detection, this DNS-based staging technique demonstrates that ClickFix continues to refine itself into a modular intrusion framework that is adaptable. 

In addition, Microsoft's Threat Intelligence team has assessed that the intrusion sequence is initiated by launching a command from the Windows Run dialog, which directly directs a DNS query to an adversary-controlled hard-coded external resolver. This command output is programmatically filtered to isolate the Name: field of the DNS response, and it is then executed as the second stage payload.

There has been documentation of this technique being used in multiple malware distribution campaigns, including campaigns that deliver Lumma Stealer. This malware has been detected in India, France, the United States, Spain, Germany, Brazil, Mexico, Romania, Italy, and Canada. 

Attributed to the GrayBravo threat actor, Lumma Stealer incorporates environmental awareness checks, identifying virtualization platforms and specific security products before decrypting and executing its payload directly in memory to evade analysis and detection. 

Rather than relying on phishing emails, malvertising networks, and drive-by download schemes, ClickFix has evolved beyond its earlier reliance on these methods to move toward DNS-based staging. By exploiting procedural trust rather than software flaws, operators persuade users to execute commands to resolve benign system problems. 

A parallel campaign distributing Lumma Stealer used CastleLoader and RenEngine Loader as primary delivery mechanisms. CastleLoader has been deployed by compromised websites that present fraudulent CAPTCHA verification prompts instructing victims to use PowerShell. 

In campaigns targeting Russian, Brazilian, Turkish, Spanish, German, Mexico, Algeria, Egypt, Italy, and France users, RenEngine Loader facilitates the deployment of Hijack Loader, which eventually installs Lumma Stealer on compromised hosts. These campaigns do not have limited operational footprints to Windows environments.

The evidence suggests that macOS-targeted infostealer activity has increased dramatically in recent years, which indicates that long-held assumptions about Apple platform immunity have been eroded. In order to capitalize on the concentration of high-value software wallets within the macOS ecosystem, attackers frequently prioritize cryptocurrency theft. 

There are numerous tactics, techniques, and procedures that macOS-specific detection strategies must consider, including unsigned applications requesting elevated credentials, anomalous Terminal execution patterns, suspicious outbound connections to blockchain infrastructure that are unrelated to financial workflows, as well as attempts to exfiltrate data from Keychain repositories and browser storage media. 

In addition to ClickFix itself, many other variants and affiliate campaigns have been launched. Security analysts have documented macOS-focused operations utilizing phishing and malvertising to distribute Odyssey Stealer, a rebranded version of Poseidon Stealer. Using compromised websites that appear legitimate, attackers have hosted deceptive CAPTCHA pages that trigger the deployment of StealC information stealer via PowerShell.

Additionally, malicious SVG files have been embedded in password-protected ZIP archives, instructing victims to execute ClickFix commands, leading to the installation of Stealerium, an open-source NET infostealer that is open-source. More unconventionally, adversaries have used public sharing features of generative AI services such as Anthropic Claude to publish staged instructions for installing the ClickFix application on macOS systems. 

Search results for macOS command-line disk space analysis tools were manipulated by a campaign resulting in redirection to a fake Medium article impersonating Apple Support, which ultimately resulted in stealer payloads being delivered by external infrastructure. These developments demonstrate how ClickFix is becoming a cross-platform social engineering framework capable of adapting to diverse malware environments by demonstrating its increasing operational flexibility. 

By creating a Windows shortcut (LNK) to the previously dropped VBScript component within the Startup directory, the malware maintains long-term access by creating persistence. By ensuring that the malicious script is executed every time the operating system boots up, the infection is embedded into the routine startup sequence of the host, ensuring long-term access to the host is maintained. 

According to Bitdefender's separate findings, Lumma Stealer activity has increased significantly as a result of ClickFix-type campaigns designed around fake CAPTCHA verification prompts. This disclosure is consistent with Bitdefender's separate findings. These operations are carried out by attackers using the AutoIt-based CastleLoader malware loader associated with GrayBravo, formerly known as TAG-150. It is linked to the threat actor GrayBravo.

After detecting virtualization platforms and specific security tools, CastleLoader decrypts and executes the stealer payload in memory, a technique designed to thwart sandbox analysis and endpoint detection. 

Furthermore, CastleLoader has been distributed via websites that advertise pirated and cracked software, as well as ClickFix-driven distribution channels. A rogue installer or executable may be downloaded by users in these scenarios, masquerading as legitimate MP4 files.

In addition, counterfeit NSIS installers have been used to execute obfuscated VBA scripts prior to starting the embedded AutoIt loader responsible for installing Lumma Stealer. Using the VBA component, these systems are reinforced by scheduled tasks designed to reinforce persistence mechanisms. 

The Bitdefender assessment indicates that, despite coordinated law enforcement actions in 2025 designed to disrupt Lumma Stealer infrastructure, Lumma Stealer has demonstrated considerable resilience. 

While shifting to alternate hosting providers, operators are rotating loaders and delivery techniques to maintain infection volumes while rapidly migrating to alternative hosting providers. Several of these campaigns remain centrally located in CastleLoader, which serves as a primary distribution tool within Lumma's broader ecosystem. As a result of analyzing CastleLoader infrastructure, it was found that domains previously identified as Lumma Stealer command-and-control servers overlapped, suggesting that the two malware clusters collaborated operationally or shared service providers. 

According to infection telemetry, the largest number of Lumma Stealer cases originate in India, followed by France, the United States, Spain, Germany, Brazil, Mexico, Romania, Italy, and Canada. In their view, ClickFix's sustained success is due not to zero-day exploits or sophisticated technical vulnerabilities but rather to the exploitation of procedural trust.

In order to reduce suspicion and increase compliance, instructions presented to victims are designed to appear like legitimate troubleshooting procedures or verification procedures. Due to this inadvertent execution of malicious code, users mistakenly believe they are resolving a routine system issue. CastleLoader is not the sole delivery mechanism facilitating Lumma Stealer's spread. 

The RenEngine Loader has also been used for campaign purposes since at least March 2025, commonly posing as game cheats or pirated commercial software such as CorelDRAW. In these attack chains, RenEngine Loader also deploys a secondary component, Hijack Loader, which installs Lumma Stealer as a result.

It is evident from these parallel loader frameworks that the Lumma distribution ecosystem is modular and adaptive, which reinforces its persistence irrespective of sustained disruption attempts. As ClickFix and its associated loader ecosystem continue to be refined, organizations must recognize a greater defensive imperative. 

Organizations cannot rely on perimeter filtering or signature-based detection alone to mitigate malicious activities originating within trusted system utilities and user workflows anymore. As part of defensive strategies, PowerShell logging should be strictly enforced, DNS queries should be monitored for anomalous patterns, and behavior detection can be used to identify command-line abuse from user-initiated processes. 

Similarly, it is crucial to implement application control policies, restrict script execution, and monitor persistent mechanisms, such as startup folder modifications and scheduled tasks, at an early stage. Training in procedural social engineering, not just phishing links and attachments, is also vital for sustained user awareness. 

Since such campaigns rely increasingly on convincing users to execute commands themselves, security programs must emphasize the risks associated with running unsolicited system instructions, regardless of how routine they appear. As ClickFix has evolved into a cross-platform, DNS-enabled staging framework, it is clear that in order to maintain defensive resilience, one must recognize and disrupt these intersections.