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

Static analysis result for SHA-256 25cf0d59c10c4815…

MALICIOUS

Office (OLE) / .XLSX

1.12 MB
MD5: ba24c9c748b75fb64abc01cc6c18ed81 SHA-1: a08173593973d23242ad28722cf60924f77fdcff SHA-256: 25cf0d59c10c48159f55b2ed560b6f3974f5b007b9b4bb31b9cfd5e33ca0bd09
140 Risk Score

Malware Insights

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

The file is an OOXML document that is encrypted with a default password and contains embedded OLE objects, specifically identified as Equation Editor objects. These objects are known exploit carriers, and the presence of an anomaly in the Ole10Native stream suggests it contains a payload. This indicates the document is designed to exploit a vulnerability in the Equation Editor to execute a malicious payload upon opening.

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.