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

Static analysis result for SHA-256 195f8028bfd632ee…

MALICIOUS

Office (OOXML) / .XLSX

804.5 KB Created: 2021-02-03 07:57:22 UTC Authoring application: Microsoft Excel 15.0300
MD5: f1564a3a6e6a3227169d136c2652eaf2 SHA-1: 6c17ecc0377cf31207087f53cf4228ed98939d3e SHA-256: 195f8028bfd632ee22ff9c3e25de3b118f0847fb21fbe91ba722ecbbfa5f2869
200 Risk Score

Malware Insights

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

The file is an Excel document containing an embedded Equation Editor OLE object that exhibits anomalies consistent with CVE-2018-0798. This vulnerability allows for arbitrary code execution, which is likely used to download and run a secondary payload. The presence of heap spray and NOP sled heuristics further supports the exploitation of a memory corruption vulnerability.

Heuristics 6

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/DYlQgcPC.TB6 contains the Equation Editor CLSID, the legacy component exploited by CVE-2017-11882, CVE-2018-0802, and CVE-2018-0798.
  • CVE-2018-0798 — anomalous Equation Editor native stream high CVE likely CVE_2018_0798_EQUATION_NATIVE_ANOMALY
    Embedded Equation Editor OLE data contains anomalous native stream bytes consistent with a CVE-2018-0798-style Equation Editor exploit. This is treated as likely CVE evidence because the Equation object is malformed and payload-like, but it does not match the exact public matrix-overflow byte signature.
  • Heap-spray pattern detected high SC_HEAP_SPRAY
    Repeated 0x41 (A) bytes found
  • 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.
  • NOP-equivalent sled detected medium SC_NOP_EQUIV_SLED
    Long run of 0x41 bytes
  • 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
9e49b27cf617b77aebe1d7f5b1f7925ea029d5a717d6dad35ac4da41adabbf41		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/DYlQgcPC.TB6 1082368 bytes
ooxml_oleobject_00_ole10native_00.bin
d1fb6450a6b22d63c6c8827066cb1b8c612036962512da63a4d87b0c91cc308d		 ole-package OOXML xl/embeddings/DYlQgcPC.TB6 Ole10Native stream: oLE10nAtiVE 1071596 bytes

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