MALICIOUS
280
Risk Score
Malware Insights
MITRE ATT&CK
T1204.002 Malicious File
T1566.001 Spearphishing Attachment
The sample is an encrypted Office XLSX file. High-severity heuristics indicate it contains an Equation Editor OLE object (OLE_EQUATION_EDITOR) that exploits CVE-2018-0798 (CVE_2018_0798_EQUATION_NATIVE_ANOMALY). This object is embedded within an exploit carrier shape (OOXML_ENCRYPTED_EXPLOIT_CARRIER_SHAPE). The file is also detected by ClamAV as Doc.Downloader.Formbook, strongly suggesting it acts as a downloader for the Formbook malware family. The encryption and malformed structure (OLE_ENCRYPTED_AND_MALFORMED) are consistent with exploit delivery mechanisms.
Heuristics 7
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Equation Editor OLE object high OLE_EQUATION_EDITORDefault-encrypted OOXML embedded OLE object xl/embeddings/oleObject1.bin contains the Equation Editor CLSID, the legacy component exploited by CVE-2017-11882, CVE-2018-0802, and CVE-2018-0798.
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CVE-2018-0798 — anomalous Equation Editor native stream high CVE likely CVE_2018_0798_EQUATION_NATIVE_ANOMALYDefault-encrypted OOXML contains embedded Equation Editor data with anomalous native stream bytes consistent with a CVE-2018-0798-style exploit. This is treated as likely CVE evidence because the Equation object is malformed and payload-like.
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Encrypted Office package with CFB FAT corruption critical OLE_ENCRYPTED_AND_MALFORMEDEncrypted-package shape co-occurs with FAT-chain corruption — the documented combined evasion form.
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ClamAV: Doc.Downloader.Formbook-bc97c1e0c33c3c93-9951465-0 critical CLAMAV_DETECTIONClamAV detected this file as malware: Doc.Downloader.Formbook-bc97c1e0c33c3c93-9951465-0
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Default-encrypted OOXML exploit carrier layout high OOXML_ENCRYPTED_EXPLOIT_CARRIER_SHAPEDefault-password encrypted OOXML package contains embedded OLE object parts and additional activation/decoy parts. This layout is common in malicious Excel exploit delivery and requires inspecting the decrypted package.
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Office document is password-encrypted medium OFFICE_ENCRYPTED_PACKAGEOLE container holds MS-OFFCRYPTO encrypted package (Standard Encryption (Office 2007, AES)).
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Office OOXML encrypted with default VelvetSweatshop password medium OFFICE_DEFAULT_PASSWORD_ENCRYPTED_OOXMLOLE EncryptedPackage decrypts with Excel's built-in VelvetSweatshop password. Office opens this transparently, and malware uses it to hide OOXML exploit parts from scanners that only inspect the outer OLE container.
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