Malicious RTF — malware analysis report

Static analysis result for SHA-256 c7a7fd06f6347b22…

MALICIOUS

RTF

1.18 MB First seen: 2022-08-31
MD5: 65e51d91d8e574ba1ec76b9fa703e526 SHA-1: 274a41c9d86d3ce1fd0a4f255ee27a953ec556e9 SHA-256: c7a7fd06f6347b22fbbe9f4bcdf29e9a47f1284321e6e70ff5a3154d2f7ca196
180 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1559.001 Component Object Model Hijacking

The RTF file contains multiple indicators of exploitation for CVE-2017-11882, specifically related to the Equation Editor. The presence of OLE objects and the ".objupdate" directive strongly suggest that the embedded Equation Editor object is designed to be activated, triggering the exploit. The decoded object data contains what appears to be VBScript code, likely intended to download and execute a second-stage 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 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off000012ab.bin
a3565b0d0ae0779162ba84fb370c4bac157457572e0af54abcff0b24f7060dfc		 rtf-objdata-decoded RTF \objdata at offset 0x12AB 146713 bytes
objdata_01_off0004ee68.bin
e1fc1a4c0e67e69e3fb71023b7446271b7980a05bfadf3f1c66142aaf4530e1c		 rtf-objdata-decoded RTF \objdata at offset 0x4EE68 187172 bytes

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