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

Static analysis result for SHA-256 c5c758ae59eab098…

MALICIOUS

Office (OLE) / .XLSX

2.54 MB
MD5: 20d9e3272cda45f81c028c6467eced77 SHA-1: b49c173b5cc90a405d08aaee459afcb7314b217d SHA-256: c5c758ae59eab0982a973c2e2e275cf132b8b470cf12557324e7faf1d540898e
140 Risk Score

Malware Insights

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

The sample is an encrypted OOXML file that contains an embedded Equation Editor OLE object. This object is known to be used as an exploit carrier, often delivering a second-stage payload. The high-confidence heuristics indicate the presence of a malicious payload within the Equation Editor object, likely exploiting a vulnerability to execute arbitrary code. No document body was extractable due to encryption, but the presence of the exploit carrier strongly suggests a malicious intent.

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.