Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 5a8ab55c281c3a08…

MALICIOUS

Office (OOXML)

610.0 KB Created: 2019-11-27 09:20:57 UTC Authoring application: Microsoft Excel 12.0000 First seen: 2021-07-10
MD5: 0aea12dc773c4d8bd340514da61f4e7d SHA-1: f574d814608afb38f501a5275042d197d92c7e97 SHA-256: 5a8ab55c281c3a08e151b0953a6cc45d146752354485ec1cfb7528dc3bfd1d17
100 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The sample is an Excel document containing an embedded OLE object, specifically identified as a Microsoft Equation Editor object. Heuristics indicate that this object carries a payload-like Ole10Native stream with an anomalous header and a significantly larger declared inner size than the stream size, strongly suggesting exploitation of a vulnerability within the Equation Editor. This technique is commonly used to execute arbitrary code, likely leading to the download and execution of a second-stage payload.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/wS8aAHM0o.yiKfxOZ contains the Equation Editor CLSID, the legacy component exploited by CVE-2017-11882, CVE-2018-0802, and CVE-2018-0798.
  • Equation Editor object carries payload-like Ole10Native stream high OLE_EQUATION_OLE10NATIVE_PAYLOAD_ANOMALY
    Embedded OLE object declares the Equation Editor CLSID but stores a large high-entropy Ole10Native stream with malformed package sizing. This is an exploit-shaped Equation/OLE payload container seen in malicious OOXML samples. It is not assigned to a specific CVE unless the MTEF/Equation Native primitive also matches.
  • Embedded OLE object medium OOXML_OLE_OBJECT
    Document contains an embedded OLE object

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
ooxml_oleobject_00.bin ooxml-ole-object OOXML embedded OLE part: xl/embeddings/wS8aAHM0o.yiKfxOZ 867328 bytes
SHA-256: 0eb4a6480279a09addade1ce0f3c01e58e96b8c01a93a1822746bb0b462692c3
ooxml_oleobject_00_ole10native_00.bin ole-package OOXML xl/embeddings/wS8aAHM0o.yiKfxOZ Ole10Native stream: OlE10naTivE 857826 bytes
SHA-256: a70d61a4e12bd9df223ee6c290e1424c731c0c878dc53fbfd43ca0356dfa8848

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