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

Static analysis result for SHA-256 c0a679b89f07e4e7…

MALICIOUS

Office (OLE) / .XLSX

1.03 MB
MD5: 0effdea228e7deed59def54efef2b37f SHA-1: dd82938468f93d2e4e58ea8ae97e8193f2ff099b SHA-256: c0a679b89f07e4e7397d033e41b6a9d577c0dde7a67e9848c3d0b576c7fbfbcf
140 Risk Score

Malware Insights

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

The sample is an encrypted OOXML file identified as an exploit carrier. It contains an Equation Editor OLE object, a common technique for delivering malicious payloads. The high entropy and anomalous stream size within the Equation Editor object suggest it contains an embedded exploit or secondary payload, though the specific nature of the payload could not be determined from static analysis alone.

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.