MALICIOUS
280
Risk Score
Malware Insights
MITRE ATT&CK
T1204.002 Malicious File
T1566.001 Spearphishing Attachment
The file is an encrypted Office document, identified as malicious by ClamAV with the signature Doc.Downloader.Formbook-bc97c1e0c33c3c93-9951465-0. Static analysis revealed an Equation Editor OLE object (CLSID offset 0x450) with anomalous native stream data, indicative of CVE-2018-0798 exploitation. The document is also flagged as an exploit carrier, containing embedded OLE objects, and exhibits CFB FAT corruption. The presence of the 'Formbook' family in the ClamAV detection strongly suggests this malware family is responsible for the malicious activity.
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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