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BlueAlpha Exploits Cloudflare Tunnels for Malicious Activities
BlueAlpha, a state-sponsored threat group from Russia, has adapted its approach to malware distribution by leveraging Cloudflare Tunnels, aiming to deploy its own GammaDrop malware on unsuspecting victims.
Cloudflare Tunnels is designed to provide secure connections to Cloudflare’s network without exposing a public IP address. This feature is intended to enhance the security of web servers and applications by shielding them from distributed denial-of-service (DDoS) attacks and direct cyber threats.
However, this legitimate tool can be manipulated by malicious entities. BlueAlpha utilizes Cloudflare Tunnels to obscure the infrastructure used for its GammaDrop operations, making detection by conventional network monitoring tools more challenging, as highlighted in a recent analysis by Recorded Future’s Insikt Group.
“Cloudflare offers the tunneling service for free through its TryCloudflare tool,” Insikt noted in its report. “This tool enables users to establish a tunnel using a randomly generated subdomain of trycloudflare.com, effectively routing all traffic through Cloudflare’s network to the designated web server.”
BlueAlpha employs this concealed infrastructure to execute HTML smuggling attacks, which evade email security measures. It also engages in DNS fast-fluxing, a technique that complicates the disruption of its command-and-control (C2) communications, ultimately facilitating the delivery of GammaDrop malware. This malware is notorious for its capabilities including data exfiltration, credential theft, and establishing backdoor access to targeted networks.
First appearing in 2014, BlueAlpha shares characteristics with other Russian threat actors, such as Trident Ursa, Gamaredon, Shuckworm, and Hive0051. Recently, the group has notably focused its attacks on Ukrainian entities through spear-phishing initiatives. BlueAlpha has also employed a specialized VBScript malware known as GammaLoad since at least October 2023.
To safeguard against such threats, Insikt Group has proposed several countermeasures:
- Enhance email security protocols to prevent HTML smuggling tactics.
- Identify and flag attachments that may contain suspicious HTML events.
- Implement application control policies to restrict the misuse of mshta.exe and untrusted .lnk files.
- Establish network rules to monitor requests aimed at trycloudflare.com subdomains.
Source
www.darkreading.com