Malicious Office (OLE) / .XLSX — malware analysis report

Static analysis result for SHA-256 7ee2d288bbb3ef8e…

MALICIOUS

Office (OLE) / .XLSX

588.4 KB
MD5: a93fa0d790d7ab691a5cecfbef32c3bc SHA-1: a3b61865c27efc91a1b2081019ddb93ee5b831a4 SHA-256: 7ee2d288bbb3ef8e4122417f9ed0346600508541188a39f3e5168a1423daa132
180 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious Link T1566 Phishing T1204.001 Malicious Link: Malicious File T1566.001 Phishing: Spearphishing Attachment

The sample is an encrypted Office XLSX file. It contains an Equation Editor OLE object, a common carrier for exploits targeting vulnerabilities such as CVE-2017-11882. The encryption and malformed structure suggest an attempt to evade static analysis and deliver a malicious payload.

Heuristics 5

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Default-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.
  • Encrypted Office package with CFB FAT corruption critical OLE_ENCRYPTED_AND_MALFORMED
    Encrypted-package shape co-occurs with FAT-chain corruption — the documented combined evasion form.
  • Default-encrypted OOXML exploit carrier layout high OOXML_ENCRYPTED_EXPLOIT_CARRIER_SHAPE
    Default-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.
  • Office document is password-encrypted medium OFFICE_ENCRYPTED_PACKAGE
    OLE container holds MS-OFFCRYPTO encrypted package (Standard Encryption (Office 2007, AES)).
  • Office OOXML encrypted with default VelvetSweatshop password medium OFFICE_DEFAULT_PASSWORD_ENCRYPTED_OOXML
    OLE 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.