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

Static analysis result for SHA-256 a45da3a772ba98f1…

MALICIOUS

Office (OLE) / .XLSX

135.8 KB First seen: 2022-06-03
MD5: 06083b03ce9335a0f47f2536b1dfa414 SHA-1: 8a7cc3cba1a5192a0969c4a44310f846d88c9fe1 SHA-256: a45da3a772ba98f18d18b10ac149c524664dc534a164200e1782bbf373d454a0
220 Risk Score

Malware Insights

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

The sample is an encrypted Office document, identified as an exploit carrier due to the presence of an Equation Editor OLE object. The critical heuristic 'OLE_ENCRYPTED_AND_MALFORMED' indicates a malformed and encrypted package, strongly suggesting it's designed to exploit vulnerabilities. Specifically, the 'CVE_2018_0798_EQUATION_NATIVE_ANOMALY' heuristic points to a known exploit vector within Equation Editor. The document's encrypted nature and the exploit carrier layout indicate it's intended to deliver a secondary malicious payload upon opening.

Heuristics 6

  • 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.
  • CVE-2018-0798 — anomalous Equation Editor native stream high CVE likely CVE_2018_0798_EQUATION_NATIVE_ANOMALY
    Default-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.
  • 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.

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