Pulsar
Pulsar is described in the provided content as a popular, well-known open-source Remote Access Trojan (RAT) targeting Windows systems. It appears in two contexts: as a payload supported by the crypter-as-a-service platform epsteincrypter[.]su, which advertised FUD encryption for .NET malware including DarkComet, Pulsar, and Quasar RAT; and as the final payload in a malicious NPM supply-chain campaign involving the typosquatted package buildrunner-dev.
In the NPM campaign, installation of buildrunner-dev triggered a postinstall script (init.js) that downloaded an obfuscated batch loader from a Codeberg repository, established persistence via the Windows Startup folder and %AppData%\protect.bat, checked for administrative rights, and used a fodhelper.exe UAC bypass to elevate privileges. The malware then launched hidden PowerShell through conhost.exe, enumerated installed antivirus products, and downloaded steganographic PNG images from ImgBB (i.ibb[.]co). These images concealed an AMSI-bypass PowerShell script, a compressed .NET loader, and a third image acting as a live C2 channel. The .NET loader used process hollowing/RunPE, AMSI bypass techniques, encryption/decryption, and reflective loading to ultimately decrypt, decompress, and load the final Pulsar payload into a legitimate Windows process.
High-confidence indicators and artifacts directly mentioned in the content include packageloader.bat, %AppData%\protect.bat, JJYDJO.exe, and the steganographic PNGs 6b8owksyv28w.png, 0zt4quciwxs2.png, and hxxps://i.ibb[.]co/tpyTL2Zg/s9rugowxbq8i.png. The campaign specifically leveraged Codeberg-hosted staging content, ImgBB-hosted steganographic payload delivery, hidden PowerShell execution, process hollowing, and UAC bypass. No specific threat actor attribution for Pulsar itself is provided in the content.
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Techniques & procedures
1 distinct technique documented for this family, organized by ATT&CK tactic.
Stealth
1 technique
Stealth
IOCs tracked for this family
4 indicators attributed across vendor reports, sandbox runs, and researcher write-ups. Full values are available in Mallory.
IPs, domains, and DNS infrastructure linked to this family.
Other indicator types observed in public reporting.
Recent activity
3 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
Remote access trojan referenced as a payload type supported by the crypter service for obfuscation/encryption.
An open-source Remote Access Trojan (RAT) delivered as the final payload in this NPM supply-chain attack; it is retrieved via steganographic PNGs and injected into a legitimate Windows process using process hollowing for stealth.
An open-source .NET Remote Access Trojan delivered via a multi-stage supply-chain attack chain (malicious NPM package -> batch/PowerShell loader -> steganographic PNG payloads -> encrypted .NET loader -> final RAT).
The version that knows your environment.
Match every observed IP, domain, and hash against your live telemetry.
Named campaigns wielding this family, with evidence pinned to each claim.
CVEs this family uses for access and lateral movement.
YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.
Every documented technique, ranked by evidence weight.
Reddit, Mastodon, and CTI community discussion around this family.