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Operation Endgame disrupted hundreds of systems — a StealC backend I reported still exposes its known routes

0
Medium
Published: 07/31/2026 (07/31/2026, 05:15:17 UTC)
Source: Reddit Malware

Description

Operation Endgame was a coordinated takedown that disrupted hundreds of malicious servers and domains associated with malware campaigns including StealC. Despite the takedown, a previously reported StealC backend infrastructure still responds on its known malware-specific API routes, returning HTTP 405 status codes, indicating the routes remain registered and reachable. However, this does not confirm that the full malware functionality, such as payload delivery or data exfiltration, remains operational. The monitoring was intermittent and showed some outages, so continuous availability is not confirmed. The takedown successfully removed GitHub typosquat repositories used for delivery, but the backend infrastructure outside GitHub remains partially accessible. This highlights that large-scale takedowns can disrupt many systems while some components may persist in a limited or dormant state.

Reddit Discussion

r/Malware·posted by u/oliver-zehentleitner
00

In April, I documented a StealC v2 campaign distributed through 19 GitHub typosquat repositories, including one impersonating my own open-source project.

The delivery chain was:

text GitHub typosquat -> Python dropper -> api.nailproxy.space -> encrypted Windows loader -> StealC v2 DLL -> spellmarketplace.club / 62.60.226.113:6673

GitHub later removed all 19 repositories.

The backend infrastructure remained a separate problem. I reported the domains, IP, malware routes, and hashes to the relevant registrars, Cloudflare, the hosting provider, CERT-Bund, GitHub Security Lab, ThreatFox, and AlienVault OTX.

Then Operation Endgame disrupted infrastructure associated with SocGholish, Amadey, and StealC. Europol reported 326 servers and 142 domains actioned. Microsoft separately said it moved against more than 200 malicious Amadey and StealC C2 domains and IPs.

Three months after my original disclosure, I checked the known infrastructure again using only minimal unauthenticated GET and HEAD requests.

The documented malware-specific routes still behave differently from an arbitrary control path:

text GET /api/v1/auth/session -> 405 Method Not Allowed GET /api/v1/data/sync -> 405 Method Not Allowed GET /foo/bar/baz -> 404 Not Found

HEAD returns the same status codes for all three paths.

This does not prove that payload delivery, authentication, or exfiltration still works. I deliberately did not send the HMAC handshake, trigger Stage 2, or interact with the malware protocol.

It does show that the known application routes remain registered and reachable.

The evidence also has limitations:

  • The monitoring cron produced only 18 measurements over 69 days.
  • There were gaps of up to 20 days.
  • The endpoints briefly became unreachable in late May.
  • GET and HEAD return different status codes on the root paths of spellmarketplace.club and the bare IP, so I do not treat those checks as proof that the complete backend is operational.

The point is not that Operation Endgame failed. It clearly disrupted a large amount of criminal infrastructure.

The narrower lesson is that both of these statements can be true:

Hundreds of malicious systems were disrupted.

A specific previously reported backend still exposes its documented malware routes.

Full technical write-up, including the original kill chain, abuse-report timeline, ThreatFox/OTX submissions, current probe results, and evidence limitations:

https://blog.technopathy.club/operation-endgame-stealc-backend-still-responds

I would be interested in how other analysts verify whether previously reported C2 infrastructure was actually included in a large takedown without actively engaging the malware protocol.

AI-Powered Analysis

Machine-generated threat intelligence

AILast updated: 09/13/2026, 17:37:20 UTC

Technical Analysis

A security researcher documented a StealC v2 malware campaign that used 19 GitHub typosquat repositories to deliver a Python dropper and ultimately a StealC DLL payload. After reporting, GitHub removed the repositories, and Operation Endgame disrupted 326 servers and 142 domains linked to StealC and other malware. Despite this, minimal unauthenticated HTTP probes conducted months later showed that the known StealC backend API routes still respond with 405 Method Not Allowed status codes, distinguishing them from arbitrary paths that return 404 Not Found. These responses indicate the malware-specific routes remain registered and reachable, though no active malware protocol interaction was performed to confirm full backend functionality. Monitoring was sporadic, with some outages observed. The backend infrastructure outside GitHub remains partially accessible, underscoring that takedown operations may not completely disable all components of a malware campaign's infrastructure.

Potential Impact

The takedown disrupted a significant portion of the StealC malware infrastructure, including removal of delivery repositories and seizure of servers and domains. However, the persistence of known backend API routes suggests that some infrastructure components remain reachable, potentially allowing limited or future malicious activity if fully reactivated. The exact operational status of the backend is unknown since no authenticated or protocol-level interactions were performed. The partial availability of backend routes could pose a risk if attackers regain full control or if residual infrastructure is leveraged in other campaigns.

Defensive Guidance

Operation Endgame and coordinated efforts by GitHub, Europol, Microsoft, and others have already disrupted much of the StealC infrastructure, including removal of delivery repositories and seizure of servers and domains. No further immediate action is required for defenders based on the current evidence, as the backend routes' availability does not confirm active malware functionality. Continued monitoring of known indicators and collaboration with law enforcement and security communities is recommended to track any resurgence or reuse of the infrastructure.

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Technical Details

Source Type
reddit
Subreddit
Malware
Reddit Score
0
Discussion Level
minimal
Content Source
reddit_link_post
Post Type
link
Newsworthiness Assessment
{"score":35,"reasons":["external_link","established_author","recent_news"],"isNewsworthy":true}
Has External Source
true
Trusted Domain
false

Threat ID: 6a6c54229c2644c7f8841bbf

Added to database: 07/31/2026, 07:52:02 UTC

Last enriched: 09/13/2026, 17:37:20 UTC

Last updated: 09/13/2026, 19:38:25 UTC

Views: 99

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