BlueDelta (APT28) uses webhook.site and Microsoft Edge to hide HOOKEDGE espionage traffic targeting European governments.
Recorded Future’s Insikt Group documented a campaign by BlueDelta, the Russian GRU-linked group that overlaps with the group APT28, running an entire espionage operation against European government targets using webhook.site, a service built for developers to test HTTP requests, as its command-and-control backbone.
The campaign ran from late September 2025 through early April 2026, targeting government and diplomatic organizations in Romania, Spain, and Türkiye.
“The campaigns delivered a lightweight Windows batch-script backdoor, dubbed “HOOKEDGE,” via macro-enabled Microsoft Word documents using diplomatic-themed lures, including material impersonating Spain’s Ministry of the Presidency, Justice and Relations with the Cortes, created shortly after a September 2025 meeting between Spanish and Moldovan officials.” states the report by Insikt Group.
“Insikt Group assesses with moderate confidence that this activity was conducted by BlueDelta (which overlaps with APT28, Fancy Bear, and Forest Blizzard), a Russian state-sponsored threat group attributed to the Main Directorate of the General Staff of the Armed Forces of the Russian Federation (GRU).”
The attackers used a fairly old-school trick: macro-enabled Word documents. One of them looked like a real meeting agenda from Spain’s Ministry of the Presidency and appeared shortly after an actual meeting between Spanish and Moldovan officials. The timing was interesting because it came just before Moldova’s September 2025 parliamentary elections. The document looked credible enough to make the phishing attempt believable.
The backdoor, called HOOKEDGE, is surprisingly simple. It uses a Windows batch script and relies on two webhooks. One receives commands, while the other sends the stolen data back to the attackers. Every 30 minutes, a scheduled task downloads a command file through Microsoft Edge, runs it and sends the results to another endpoint. The malware uses Edge to make the traffic look like normal web activity, making it harder for security tools to spot.
That reliance on a real browser for both tasking and exfiltration is the cleverest part of the whole design.
“A notable aspect of HOOKEDGE is its use of msedge.exe for both tasking and exfiltration. By generating network traffic through a legitimate web browser rather than a commonly abused LotL binary (LOLBin) or a custom binary, the malware blends its communications with normal enterprise browsing activity.” continues the report.
Recorded Future explains, and that’s really the entire evasion strategy in one sentence: don’t build something exotic, just make your traffic look exactly like an employee checking a website.
BlueDelta didn’t build HOOKEDGE from scratch either. It shares deep code and structural overlap with HEADLACE, a backdoor the same group used years earlier, right down to identical JavaScript variable names and the same base64 encoding scheme for automated downloads.
“HOOKEDGE’s code and structural design have significant overlap with HEADLACE, a backdoor used by BlueDelta in previous campaigns.” states the report.
Recorded Future assesses with moderate confidence that HOOKEDGE is a direct evolutionary successor, maintained by the same operators rather than a fresh tool built by a different team, which fits BlueDelta’s long-documented habit of refining working tradecraft instead of reinventing it.
The operation also included a triage mechanism worth understanding on its own. Once a victim showed signs of being worth deeper attention, active communication with the initial webhook endpoints, BlueDelta deployed a second HOOKEDGE payload configured to check in every five minutes instead of thirty, giving operators much faster interactive control over higher-value targets. That two-tier setup also solved a practical infrastructure problem: webhook.site’s free tier caps out at 100 requests per endpoint, so spreading routine and high-priority tasking across separate endpoints kept any single one from getting exhausted mid-operation.
BlueDelta kept tuning the operation continuously rather than treating it as a finished product. Beaconing intervals stretched from 30 minutes to 61, deliberately timed to slip past sandbox environments that typically only watch a sample’s behavior for an hour. The group added canary tracking pixels named things like mailopened.jpg and docopened.jpg to monitor exactly when a phishing email got opened versus when the document itself got opened versus when macros actually executed, essentially building analytics for their own phishing funnel.
“The malicious document also contains a hidden image referencing a remote webhook URL: hxxp://webhook[.]site/62114596-33f5-47fb-9012-0223529e5a13/docopened[.]jpg. This serves as a document-open “canary,” alerting BlueDelta operators when a victim opens the lure. Later variants used the filename doc.jpg in place of docopened.jpg.” states Insik. “Insikt Group also identified webhooks using the filename mailopened.jpg, indicating that BlueDelta likely used a similar canary mechanism to monitor when recipients opened phishing emails, providing operators with visibility into campaign delivery success before any payload execution.”
That kind of detailed tracking of what victims do would look very familiar to a marketing team. The difference is that here the targets are victims, not customers.
For defenders, the useful indicators are quite clear. Block macros in documents downloaded from the internet, monitor scheduled tasks that launch scripts from user-writable folders, and flag Microsoft Edge running in headless mode or making automated connections to file-sharing and webhook services that the organization does not normally use. You don’t need sophisticated tools to spot these behaviors. Even a well-configured monitoring system should be able to detect them early. The worrying part is that a persistent, state-backed group can still rely on a small set of behaviors that defenders can identify and block.
For defenders, the actionable pieces here are concrete rather than abstract. Block macro execution from documents that arrived over the internet, watch for scheduled tasks spawning script interpreters from user-writable folders, and specifically flag Microsoft Edge running in headless mode or making automated requests to file-hosting and webhook services your organization doesn’t actually use for anything legitimate. None of this requires exotic tooling to catch, which is oddly reassuring: a threat group this persistent and state-backed is still, at its core, relying on the same handful of detectable behaviors that a properly configured monitoring setup would catch on day one.
“BlueDelta is likely to continue conducting initial access campaigns against European government and diplomatic organizations in support of Russian intelligence collection. Given the enduring strategic importance of European governance, NATO-related affairs, and diplomatic engagement with former Soviet republics, the intelligence requirements driving this activity are unlikely to diminish in the near term.” concludes the report.
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Source: SecurityAffairs
Source Link: https://securityaffairs.com/197996/apt/russian-apt-bluedelta-uses-hookedge-to-target-defense-and-diplomatic-organizations.html