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

Static analysis result for SHA-256 b3ca40ad0ec4051b…

MALICIOUS

Office (OLE) / .XLSX

1.25 MB
MD5: 3f262200b6de3e0ada1b4f68fa0897f8 SHA-1: 8c57eb2b303a36cb7c0b6fb4a6a5ff189371017b SHA-256: b3ca40ad0ec4051b7e28efa68de773cb2f048ba459859732f414a12bb2e69fac
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 embedded OLE objects, specifically identified as an Equation Editor object. This type of object is frequently used as an exploit carrier. The anomaly detected in the Ole10Native stream suggests it contains a payload. Given the nature of the embedded object and its anomalous stream, it is highly likely intended to deliver a secondary exploit or 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.