NanoCore Sample Detected: Backdoor.exe

This article was originally published on ThreatChain — decentralized threat intelligence.

An attacker is reading your keystrokes, watching your screen, and downloading your files. The RAT that infected you cost $25.

A new NanoCore sample was identified by threat intelligence feeds on 2026-05-27 09:35:06. This post breaks down what we know about the specific sample, how to recognize related activity on your network, and what to do if you or your organization might be affected.

The Sample at a Glance

What NanoCore Does

NanoCore is a malware family observed delivering malicious payloads to Windows systems. Samples in this family typically steal credentials, establish persistence, or enable remote access for attackers.

Seeing this family on your network — or finding a file matching this hash — is a red flag. NanoCore samples are typically distributed through phishing emails, malvertising, fake software downloads, or cracked installers. Once executed, the malware usually establishes persistence on the host, harvests credentials and sensitive data, and establishes an outbound channel to command-and-control infrastructure operated by the attackers.

Detection Landscape

Multiple security vendors have weighed in on this specific sample:

• ANY.RUN: [{'malware_family': 'nanocore', 'verdict': 'Malicious activity', 'file_name': 'Backdoor.exe', 'date': '2026-05-26 11:19:54', 'analysis_url': 'https://app.any.run/tasks/9703f8a8-90de-45d8-b906-e69f1e074894', 'tags': ['auto-sch-xml', 'auto-reg', 'nanocore', 'rat', 'remote']}]
• CERT-PL_MWDB: nanocore
• vxCube: malware2
• Intezer: malicious
• CAPE: NanoCore
• Triage: nanocore
• Spamhaus_HBL: [{'detection': 'malicious', 'link': 'https://www.spamhaus.org/hbl/'}]
• UnpacMe: [{'sha256_hash': 'a2a68b45676bf44538f2effae4064ba2124ca759b21e801bc7dd855a2bd9f254', 'md5_hash': 'a3bf3b8d6e8242de1859665f9272e4fb', 'sha1_hash': '7a97ee0624781c95654ca4641d4c3a3e14276a1f', 'detections': ['win_nanocore_w0', 'triage_nanocore_rat'], 'link': 'https://www.unpac.me/results/edc6d070-bb7a-4564-a16c-2d16f434788e/'}, {'sha256_hash': '61e9d5c0727665e9ef3f328141397be47c65ed11ab621c644b5bbf1d67138403', 'md5_hash': 'bdc8945f1d799c845408522e372d1dbd', 'sha1_hash': '874b7c3c97cc5b13b9dd172fec5a54bc1f258005', 'detections': ['triage_nanocore_rat'], 'link': 'https://www.unpac.me/results/edc6d070-bb7a-4564-a16c-2d16f434788e/'}, {'sha256_hash': '01e3b18bd63981decb384f558f0321346c3334bb6e6f97c31c6c95c4ab2fe354', 'md5_hash': '9c8242440c47a4f1ce2e47df3c3ddd28', 'sha1_hash': '874f3caf663265f7dd18fb565d91b7d915031251', 'detections': ['triage_nanocore_rat'], 'link': 'https://www.unpac.me/results/edc6d070-bb7a-4564-a16c-2d16f434788e/'}, {'sha256_hash': 'f9b8c3f31375e9a1ec105f930f751869a804110d29d6b38e7298622eb74b2bec', 'md5_hash': '42006852619847f368bc4062849cd6dc', 'sha1_hash': 'ba6edc3a5aba8eac15b6a30e1407cdae80b2481d', 'detections': [], 'link': 'https://www.unpac.me/results/edc6d070-bb7a-4564-a16c-2d16f434788e/'}]
• VMRay: NanoCore
• FileScan-IO: MALICIOUS

Indicators of Compromise

If you're hunting for this sample or related NanoCore activity, here are the concrete indicators to feed into your SIEM, EDR, or host-based searches:

• SHA-256 hash: a2a68b45676bf44538f2effae4064ba2124ca759b21e801bc7dd855a2bd9f254
• Filename pattern: Backdoor.exe
• File type: exe
• Behavioral tags: exe, NanoCore, RAT
• YARA rules matched: ach_NanoCore, malware_Nanocore_strings, MALWARE_Win_NanoCore, Nanocore, nanocore_rat

How to Check If You're Affected

1. Search your endpoint logs for the SHA-256 a2a68b45676bf44538f2effae4064ba2124ca759b21e801bc7dd855a2bd9f254. Most EDR platforms support historical hash searches across all monitored hosts.
2. Check for the filename Backdoor.exe in recently downloaded files, email attachments, and installer bundles.
3. Look for outbound connections to uncommon TLDs or newly registered domains — NanoCore typically beacons to command-and-control infrastructure shortly after execution.
4. Review scheduled tasks and registry run keys — this family commonly establishes persistence through standard Windows autorun locations.
5. Run an updated AV or EDR scan across potentially affected hosts. Because this sample is already in public threat intel feeds, current signatures should flag it.

What to Do If You Find It

If you find evidence of this sample or related activity on your systems:

1. Isolate the affected host from the network immediately to prevent lateral movement.
2. Capture memory and disk images before rebooting. Reboots destroy critical forensic evidence, especially in RAM.
3. Rotate credentials that may have been exposed — browser-saved passwords, VPN credentials, SSH keys, and any service accounts used on the affected host. NanoCore frequently targets these.
4. Check for secondary payloads. NanoCore is often a stepping stone for additional malware including ransomware or banking trojans.
5. Report the incident to your security team. For larger organizations, consider notifying your regional CERT.

Free Threat Lookups

You can verify any suspicious hash against the ThreatChain database for free — no signup, no API key required. Paste any MD5, SHA-1, or SHA-256 at threatchain.io/lookup and get results across multiple intel sources in seconds.

For cross-referencing this specific sample, you can also look it up directly on MalwareBazaar where the original submission and vendor analysis is recorded.