Malicious RTF — malware analysis report

Static analysis result for SHA-256 5f04aeab5b9d0ae2…

MALICIOUS

RTF

12.4 KB
MD5: 1f542211ce3f36ab19dcca8d32998a66 SHA-1: f3a34ade29c53134ddf2340a1b1506d8d48b6ddd SHA-256: 5f04aeab5b9d0ae2cfee2e6e5d50d36f0ee8634af022bfd9e7220157cf2545a9
180 Risk Score

Malware Insights

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

The RTF document contains an embedded OLE object specifically identified as an Equation Editor object, which is known to be vulnerable to CVE-2017-11882. The presence of RTF_EQUATION_EDITOR and CVE_2017_11882_ACTIVATION_RELATED heuristics strongly indicates exploitation of this vulnerability. This technique allows for arbitrary code execution, likely to download and run a secondary payload.

Heuristics 5

  • Equation Editor activation — CVE-2017-11882 related high CVE related CVE_2017_11882_ACTIVATION_RELATED
    RTF decodes to an Equation.3 ProgID and requests OLE activation with \objemb plus \objupdate. This reaches the legacy Equation Editor attack surface used by CVE-2017-11882/CVE-2018-0802 documents, but the malformed MTEF/native payload needed for stronger 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.
  • OLE object data medium RTF_OBJDATA
    RTF contains 1 \objdata section(s) — embedded OLE objects
  • Embedded OLE object medium RTF_OBJEMB
    RTF contains \objemb — embedded OLE object

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00001dda.bin
d5982e04ed5e6de364e957d111cef04a57c9b2e7623a14e1bb9dd6114e878509		 rtf-objdata-decoded RTF \objdata at offset 0x1DDA 1864 bytes

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