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ManageEngine title graphic reading AOMEI Backupper supply-chain compromise: Investigation and analysis over a dark globe, candlestick chart and red warning triangles.
Graphic: ManageEngine METAL, article title art for AOMEI Backupper supply-chain compromise: Investigation and analysis, Oct 16, 2026 (fair use).

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Mandiant and ManageEngine Say UNC7017 Poisoned AOMEI Backupper Updates in Five-to-Ten-Minute Bursts, Then Restored Clean Files to Hide a Radmin-Sideloaded Backdoor

Google Threat Intelligence Group, Mandiant and ManageEngine's METAL lab say UNC7017 rewrote two unauthenticated AOMEI update files for minutes at a time, so analysts who checked the vendor's servers later saw clean files while endpoints kept a scheduled-task backdoor or were coerced into sending NTLM hashes.

James Whitford, ToolsAustin5 min read

AUSTIN - Google Threat Intelligence Group and Mandiant said on Oct. 15, 2026 that a threat cluster they track as UNC7017 compromised the update infrastructure of AOMEI Technology, the maker of the AOMEI Backupper backup tool and the AnyViewer remote desktop product, by rewriting the vendor's remote configuration files for only five to ten minutes at a time before putting the authentic versions back. GTIG called it the first software supply chain compromise it has encountered that was run in windows that short, "effectively evading traditional point-in-time triage and automated file scanning." Any client that polled AOMEI's servers during a window received malicious instructions; clients that checked before or after got clean files. ManageEngine's Threat Analysis Lab, known as METAL, whose endpoint detection and response telemetry first flagged the activity in late May, published its own investigation on Oct. 16. GTIG said affected organizations included IT services, telecommunications and higher education entities in Australia, Brazil, India, Pakistan, Portugal, Singapore, South Africa, Spain, Switzerland, Türkiye and the United States, and that victimology was opportunistic and likely extends beyond the organizations it directly identified.

GTIG diagram showing AOMEI Backupper and AnyViewer services polling down_html.ini and Notifycfg.ini over HTTPS, with the clean vendor flow above UNC7017's five-minute tampering that redirects to attacker staging and deploys the CROSSROAD loader.
Graphic: Google Threat Intelligence Group and Mandiant, AOMEI software update mechanism, normal versus malicious flow, Oct 15, 2026 (fair use).The diagram contrasts AOMEI's normal update poll with UNC7017's short tampering window.

The attack rode AOMEI's own plumbing. Background services Backupper.exe and ABNotify.exe poll two files over HTTPS: down_html.ini, which names the update package, its version and its expected MD5 hash, and Notifycfg.ini, which tells ABNotify.exe which messages to display and which local programs to run. METAL notes that neither file is cryptographically authenticated by the client and that the checksum used to validate the archive is declared inside the same unauthenticated file that names it, and writes that "nothing in this attack exploited a software defect." GTIG lists three directly observed windows: May 28 from 05:40 to 05:50 UTC, July 16 from 08:33 to 08:39 UTC and July 20 from 10:35 to 10:40 UTC. In each, UNC7017 pointed the download at its own staging host, promotion.storage-data.com, bumped the build number and matching MD5 so the client would accept the archive, and on July 16 padded Notifycfg.ini with more than 35,000 lines of dummy sections to force the update and run the dropper. On July 20 it switched the first download to a public Google Cloud Storage bucket, which GTIG says let the request slip past enterprise proxies that block newly registered domains.

Ten-step METAL diagram from Backupper.exe polling and archive extraction through ABNotify.exe launching upgrade-now.exe, Radmin install, BlkScrDl.dll side-loading, the RadminComponentRuntime scheduled task and C2 check-in.
Graphic: ManageEngine METAL, AOMEI Backupper compromise execution chain from tampered configuration to implant check-in, Oct 16, 2026 (fair use).The chain stays inside AOMEI's own update path until the tampered configuration takes over.

METAL's account shows why the campaign was so hard to prove. On May 28, ManageEngine EDR recorded AOMEI Backupper installing the Radmin remote administration tool on two unrelated customer endpoints in different countries. By the time a customer raised the alert on June 7, the dropper had deleted itself and its hash was unknown to VirusTotal, AOMEI's initial explanation was that the content had been intercepted in transit, and METAL's own reproduction of the update path served nothing malicious. The lab trusted the telemetry instead. A misspelled product string in the dropper's metadata, "AOMEI Update Compent," led it to a matching sample that every VirusTotal engine had classified as benign. METAL then placed continuous monitors on the delivery URLs and on July 16 caught the served content and its hash change and revert within minutes. It handed its full attack profile to Mandiant on July 17, and Mandiant captured the July 20 window independently while METAL's monitor was down. Mandiant notified AOMEI on July 17; AOMEI said on July 29 that it had taken corrective action.

Timeline with six entries: May 28 detection on two endpoints, June 7 escalation and AOMEI notification, June reconstruction, July 16 tampering captured, July 17 shared with Mandiant, July 20 second window captured by Mandiant.
Graphic: ManageEngine METAL, investigation timeline from the May 28 detection to the July 20 second window, Oct 16, 2026 (fair use).METAL's timeline runs from the May 28 detection to Mandiant's July 20 capture.

The payload chain is built to look like trusted software. The CROSSROAD loader, delivered as upgrade-now.exe, checks the host's public IP through reflection services and halts if it geolocates to China; METAL says it also stops when geolocation fails or specific endpoint security agents are present. It then restores the local down_html.ini to AOMEI's legitimate values, unpacks a Radmin bundle and registers a scheduled task named RadminComponentRuntime that runs the genuine, Famatech-signed FamItrfc.exe with the flag --runtimechk every three hours, before deleting itself through an NTFS alternate data stream. The signed binary side-loads an attacker-built BlkScrDl.dll, which registers RuntimeComponent.dll as a COM server; that component decrypts a ChaCha20 payload and runs Python bytecode in an embedded PocketPy interpreter, the SHINYROAD backdoor, which calls out to 8.218.65.184. METAL found Radmin Server installed but never armed, with no listener or credential; remote access depended on the implant connecting out. In mid-July, GTIG says, UNC7017 also pushed ADAPTAGENT, the client of the Adaptix C2 framework, disguised as Nitro PDF software under a scheduled task named NitroRuntime and beaconing every two minutes to 8.210.84.56. On July 20 the actor replaced a "World Cup Deals" banner with an invisible one-by-one-pixel window at priority 9999 that pointed to a WebDAV path on that same address, a way to coerce NetNTLMv2 hashes with no code execution at all. METAL warns that endpoints where the dropper aborted may still have leaked credentials through that path.

Configuration text pointing the AOMEI popup at a local upgrade-now.html file with Width=1, Height=1 and Priority=9999.
Screenshot: ManageEngine METAL, Notifycfg.ini as served during the July 16 tampering window (fair use).The tampered configuration points the popup at a local one-by-one-pixel page.

For SOC teams, GTIG names a specific triage trap. When EDR flags a suspicious child process from an updater, analysts often check the vendor's download URL or its reputation, see authentic files and close the alert as a false positive. GTIG says responders should instead preserve the endpoint-cached configuration files under %PROGRAMFILES(X86)%\AOMEI\*\Tmphtml\ and review proxy and firewall telemetry for the exact second the alert fired. Server-side fixes do not disinfect endpoints that pulled payloads earlier, so organizations running AOMEI software should hunt retroactively across April through July: unauthorized \RadminComponentRuntime and \NitroRuntime tasks, unsigned BlkScrDl.dll in %LOCALAPPDATA%\Radmin\ alongside a signed FamItrfc.exe, Eztwain4.dll in %LOCALAPPDATA%\Nitro Pro\, executables running from AOMEI's html\ directory, and the User-Agent Anyviewer-loader/1.0. GTIG recommends blocking storage-data.com and its subdomains, 8.210.84.56, 47.239.60.117 and 8.218.65.184, and blocking outbound SMB on TCP 445 and WebDAV to external addresses. Its report publishes file hashes, the tampered .ini hashes, YARA detection rules including one for CROSSROAD, and the Google Security Operations rules that fire on the activity. For vendors, GTIG's advice is to sign remote configuration files, verify Authenticode signatures before extraction, pin update destinations, refuse file:// and UNC paths in in-app popups, and separate core updates from marketing channels. GTIG attributes the activity only to the threat cluster it tracks as UNC7017 and does not tie it to a named group or country in the report.

Sources:


James Whitford covers SOC tooling, SIEM, SOAR, and detection platforms for SOCtember from Austin.

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