Malicious RTF — malware analysis report

Static analysis result for SHA-256 d3d5ee8f95c5d96e…

MALICIOUS

RTF

27.4 KB First seen: 2020-09-15
MD5: 58307df23ed552b77bb6c2b8f7c8554d SHA-1: 18211153dce0fbc49ef8d483a8a8dd3117e74eb8 SHA-256: d3d5ee8f95c5d96ecb335d22494ccf6d5481a2001cf12e9a9f0c3d7817c4d70a
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 that exploits the Equation Editor vulnerability (CVE-2017-11882). This vulnerability allows for arbitrary code execution when the object is activated, likely leading to the download and execution of a secondary payload. The presence of the specific ProgID 'eQUaTIoN.3' is a strong indicator of this exploit.

Heuristics 5

  • Split hex Equation Editor ProgID + OLE object critical CVE likely 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.
  • 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.
  • \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_off00001a3e.bin rtf-objdata-decoded RTF \objdata at offset 0x1A3E 1683 bytes
SHA-256: 7f977861c8395f9e7a549e9fcd8e3ef62f5f7fb9c5242afc1bcb1d9c2d8aa2e9

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