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

Static analysis result for SHA-256 d9b757bd25d0727b…

MALICIOUS

Office (OLE) / .XLSX

1.27 MB
MD5: ccfbf0e942de09df4d6b94a6a08cd522 SHA-1: 55c1606e1da313503649e56a96e5ceae151fff27 SHA-256: d9b757bd25d0727b73281b3a0321a7d926a01a77e66b2fd542ee8ce10470528b
140 Risk Score

Malware Insights

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

The sample is an OOXML file encrypted with a default password, indicating an attempt to hide its malicious contents. It contains an embedded Equation Editor OLE object, which is a known carrier for exploits. The 'OLE_EQUATION_EDITOR' and 'OLE_EQUATION_OLE10NATIVE_PAYLOAD_ANOMALY' heuristics strongly suggest this object is used to deliver a second-stage payload, likely exploiting a vulnerability within the Equation Editor itself.

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.