Malicious RTF — malware analysis report

Static analysis result for SHA-256 3354eae53ca3d8b2…

MALICIOUS

RTF

1.54 MB First seen: 2022-05-25
MD5: e540cd8817c6cc5a1af332ee60f0e7bb SHA-1: 1bd7814281ab30d8562541537dac2f285399cf00 SHA-256: 3354eae53ca3d8b2e1a317af94069d28e784f9d60c46b2099bf082181a892e61
220 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1559.001 Component Object Model and Distributed Component Object Model: Component Object Model

The RTF document contains multiple critical heuristic firings indicating the exploitation of CVE-2017-11882 through a malformed Equation Editor OLE object. The presence of OLE object data and excessive hex data further supports the hiding of a payload within the document. The ".bin" file extracted from the OLE object is likely the second-stage payload.

Heuristics 5

  • Equation Editor OLE1 native payload — CVE-2017-11882 related critical CVE related CVE_2017_11882_RELATED
    RTF decodes to an OLE1 Equation.3 embedded object whose native data is large and payload-like, and \objupdate requests automatic activation. This is the delivery shape used by Equation Editor RCE documents such as CVE-2017-11882/CVE-2018-0802, but the malformed MTEF record needed for exact attribution was not recovered.
  • Split hex Equation Editor ProgID + OLE object critical RTF_EQUATION_EDITOR
    RTF embeds the Equation.3 ProgID as hex bytes near OLE object activation and splits the byte stream with whitespace or an ignorable RTF group. This is an Equation Editor OLE activation surface commonly used by CVE-2017-11882 / CVE-2018-0802 exploit documents.
  • \objupdate forces OLE activation high RTF_OBJUPDATE
    RTF contains \objupdate — forces automatic OLE object instantiation when the document is opened, bypassing user interaction. Almost exclusively seen in Equation Editor exploit documents.
  • Large hex data blocks in OLE object high RTF_EXCESSIVE_HEX
    RTF contains ~1614KB of hex-encoded data inside \objdata sections — may hide a payload
  • OLE object data medium RTF_OBJDATA
    RTF contains 2 \objdata section(s) — embedded OLE objects

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off000012b8.bin
56ba1c28cbd41549ff4b1608fb2ffce4c2e8f50fa17ad9d39f7d5f118a7ff53d		 rtf-objdata-decoded RTF \objdata at offset 0x12B8 807454 bytes

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