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

Static analysis result for SHA-256 301931ba01dbd223…

MALICIOUS

Office (OLE) / .XLSX

1.13 MB
MD5: 49f4190f49803e7fb70651fd3401f7a9 SHA-1: c6b213ecad3b1c9f75e1cd631f04af6aa9b8e5b5 SHA-256: 301931ba01dbd223bf81f7c64a5bad3ce1663e4930776807fe30acd8951067df
140 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File

The sample is an encrypted OOXML file that contains an Equation Editor OLE object. This object is a known technique for delivering malicious payloads, often exploiting vulnerabilities in the Equation Editor itself. The high-entropy Ole10Native stream within the Equation Editor object suggests it is packed with a payload. The default encryption further indicates an attempt to hinder analysis.

Heuristics 4

  • 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.
  • 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.
  • Equation Editor object carries payload-like Ole10Native stream high OLE_EQUATION_OLE10NATIVE_PAYLOAD_ANOMALY
    Default-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.
  • 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.