MALICIOUS
280
Risk Score
Malware Insights
MITRE ATT&CK
T1566.001 Spearphishing Attachment
T1203 Exploitation for Client Execution
The file is a password-encrypted XLSX document that contains an embedded Equation Editor OLE object. Heuristics indicate this object exploits CVE-2018-0798, a vulnerability in Equation Editor, to execute arbitrary code. The ClamAV detection name 'Doc.Downloader.Formbook' strongly suggests the Formbook family, which is known for its downloader capabilities. The embedded OLE object likely serves as the initial execution vector to download and run a secondary payload.
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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