A "simplified Chinese-speaking actor" has been linked to a new campaign that has targeted multiple countries in Asia and Europe with the end goal of performing search engine optimization (SEO) rank manipulation.
The black hat SEO cluster has been codenamed DragonRank by Cisco Talos, with victimology footprint scattered across Thailand, India, Korea, Belgium, the Netherlands, and China.
"DragonRank exploits targets' web application services to deploy a web shell and utilizes it to collect system information and launch malware such as PlugX and BadIIS, running various credential-harvesting utilities," security researcher Joey Chen said.
The attacks have led to compromises of 35 Internet Information Services (IIS) servers with the end goal of deploying the BadIIS malware, which was first documented by ESET in August 2021.
It's specifically designed to facilitate proxy ware and SEO fraud by turning the compromised IIS server into a relay point for malicious communications between its customers (i.e., other threat actors) and their victims.
On top of that, it can modify the content served to search engines to manipulate search engine algorithms and boost the ranking of other websites of interest to the attackers.
"One of the most surprising aspects of the investigation is how versatile IIS malware is, and the [detection of] SEO fraud criminal scheme, where malware is misused to manipulate search engine algorithms and help boost the reputation of third-party websites," security researcher Zuzana Hromcova told The Hacker News at the time.
The latest set of attacks highlighted by Talos spans a broad spectrum of industry verticals, including jewelry, media, research services, healthcare, video and television production, manufacturing, transportation, religious and spiritual organizations, IT services, international affairs, agriculture, sports, and feng shui.
The attack chains commence with taking advantage of known security flaws in web applications like phpMyAdmin and WordPress to drop the open-source ASPXspy web shell, which then acts as a conduit to introduce supplemental tools into the targets' environment.
The primary objective of the campaign is to compromise the IIS servers hosting corporate websites, abusing them to implant the BadIIS malware and effectively repurposing them as a launchpad for scam operations by utilizing keywords related to porn and sex.
Another significant aspect of the malware is its ability to masquerade as the Google search engine crawler in its User-Agent string when it relays the connection to the command-and-control (C2) server, thereby allowing it to bypass some website security measures.
"The threat actor engages in SEO manipulation by altering or exploiting search engine algorithms to improve a website's ranking in search results," Chen explained. "They conduct these attacks to drive traffic to malicious sites, increase the visibility of fraudulent content, or disrupt competitors by artificially inflating or deflating rankings."
One important way DragonRank distinguishes itself from other black hat SEO cybercrime groups is in the manner it attempts to breach additional servers within the target's network and maintain control over them using PlugX, a backdoor widely shared by Chinese threat actors, and various credential-harvesting programs such as Mimikatz, PrintNotifyPotato, BadPotato, and GodPotato.
Although the PlugX malware used in the attacks relies on DLL side-loading techniques, the loader DLL responsible for launching the encrypted payload uses the Windows Structured Exception Handling (SEH) mechanism in an attempt to ensure that the legitimate file (i.e., the binary susceptible to DLL side-loading) can load the PlugX without tripping any alarms.
Evidence unearthed by Talos points to the threat actor maintaining a presence on Telegram under the handle "tttseo" and the QQ instant message application to facilitate illegal business transactions with paying clients.
"These adversaries also offer seemingly quality customer service, tailoring promotional plans to best fit their clients' needs," Chen added.
"Customers can submit the keywords and websites they wish to promote, and DragonRank develops a strategy suited to these specifications. The group also specializes in targeting promotions to specific countries and languages, ensuring a customized and comprehensive approach to online marketing."
