MALICIOUS
280
Risk Score
Malware Insights
MITRE ATT&CK
T1203 Exploitation for Client Execution
T1566.001 Spearphishing Attachment
The file is an encrypted OOXML document identified by ClamAV as Xls.Downloader.af2fa5c5d0587870-9978799-0. High-severity heuristics indicate the presence of an Equation Editor OLE object that carries a payload-like stream, suggesting it's designed to exploit a vulnerability for client execution. The document's encrypted nature and the embedded exploit carrier point towards a spearphishing attachment delivery method.
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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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: Xls.Downloader.af2fa5c5d0587870-9978799-0 critical CLAMAV_DETECTIONClamAV detected this file as malware: Xls.Downloader.af2fa5c5d0587870-9978799-0
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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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Equation Editor object carries payload-like Ole10Native stream high OLE_EQUATION_OLE10NATIVE_PAYLOAD_ANOMALYDefault-encrypted OOXML embedded OLE object declares the Equation Editor CLSID but stores a large high-entropy Ole10Native stream with malformed package sizing. This is exploit-shaped Equation/OLE payload evidence.
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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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