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

Static analysis result for SHA-256 821f2880a8218afc…

MALICIOUS

Office (OLE) / .XLSX

1.18 MB
MD5: 25f7735ff71a70abf4bb508d2711f50b SHA-1: 7f40fff223019a3e399ca0ae0990afaf2695e93b SHA-256: 821f2880a8218afc0d30711b46f7d28e9adb2cd6c3db88b881de91090e72337f
140 Risk Score

Malware Insights

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

The sample is an encrypted Excel file that utilizes a default password, a common technique for obfuscating malicious content. It contains an embedded Equation Editor OLE object, which is frequently used to deliver exploits. The presence of an anomalous Ole10Native stream within the Equation Editor object further indicates it's likely carrying a malicious payload, although the specific nature of the payload cannot be determined from the provided heuristics.

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.