Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 5a826d3740abc351…

MALICIOUS

RTF / .DOC

21.3 KB
MD5: d6258119e8fa82468f7066362b0ac76c SHA-1: 413397a3f9580a062f8f05114cec0da16f450412 SHA-256: 5a826d3740abc3511046dacb3ac06a7cdfcf2a69c6d24c4ff3b9fb2e76b28e01
200 Risk Score

Malware Insights

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

The RTF file contains embedded OLE object data and specifically triggers heuristics related to the Equation Editor vulnerability (CVE-2017-11882). This vulnerability allows for arbitrary code execution, which is the primary mechanism for this attack. The presence of ".objupdate" further indicates an attempt to force OLE object activation. The exact payload or subsequent actions are not detailed in the provided evidence, but the exploit itself is the main finding.

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.
  • Automatically linked OLE object high RTF_OBJAUTLINK
    RTF contains \objautlink — an automatically linked OLE object surface that can be updated or activated when Word opens the document.
  • \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

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00001a06.bin
36ec570ae1208982c11a5018759b7b47cdb78fda9907ca1808b052a95ce5d1ef		 rtf-objdata-decoded RTF \objdata at offset 0x1A06 1490 bytes

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