Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 0e062bc20a20f878…

MALICIOUS

RTF / .DOC

60.8 KB
MD5: ca81cad23c804a7d4ab335ca80eac1d2 SHA-1: eb67c16e0306699060f69036bff2270b0b2342c3 SHA-256: 0e062bc20a20f878a6beecab28a4021027ac7bf1ae8c887f7b8b8daebb245c62
180 Risk Score

Malware Insights

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

The sample is an RTF document that contains embedded OLE object data, specifically related to Microsoft Equation Editor. Heuristics indicate a critical firing for RTF_EQUATION_EDITOR and high firings for CVE_2017_11882_ACTIVATION_RELATED and RTF_OBJUPDATE, strongly suggesting exploitation of the CVE-2017-11882 vulnerability. This vulnerability allows for arbitrary code execution, which is typically used to download and execute a secondary malicious 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 2 \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_off00001aa9.bin
4e6099056d227316bb09bb73fc85d24e1b702490c3ce9394d04a3b272bc01251		 rtf-objdata-decoded RTF \objdata at offset 0x1AA9 1809 bytes

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