Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 ac32a1e6ae4396b3…

MALICIOUS

RTF / .DOC

36.9 KB First seen: 2023-02-01
MD5: af48f996012aa84711c7d65663e1515c SHA-1: 5698857cc572dcca43a21fd89ac2f68081f1597f SHA-256: ac32a1e6ae4396b358a90a8c11686346cf1951c4e51eab84960dd8f307d20aa3
200 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File T1059.005 Visual Basic

The file is an RTF document containing an embedded OLE object specifically crafted to exploit the Equation Editor vulnerability (CVE-2017-11882). The presence of RTF_EQUATION_EDITOR and CVE_2017_11882_ACTIVATION_RELATED heuristics strongly indicates this exploit. The SE_ENABLE_LURE heuristic suggests the document likely contains a prompt to enable editing or macros, a common social engineering tactic to trick users into activating the exploit.

Heuristics 6

  • 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
  • Macro/content-enable lure medium SE_ENABLE_LURE
    Document instructs the user to enable macros or editing — a common technique used by malware droppers to bypass Office macro security settings

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00004c64.bin
6077cb0e59d16583fef821b441bf6b003f4f620fdce74b6a24377e3c48b6faa7		 rtf-objdata-decoded RTF \objdata at offset 0x4C64 1719 bytes

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