Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 03b90ec51e4a17ab…

MALICIOUS

RTF / .DOC

1.45 MB First seen: 2023-10-09
MD5: 78481380a22eb714005799312e038064 SHA-1: 1a5828b9e7e5ef9b04feceeb181b760a28d86ccf SHA-256: 03b90ec51e4a17ab15c069f808ad76d3e5218aa058ee961e63c1fa8cc1ac0e5c
180 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution

The sample contains multiple indicators of exploiting CVE-2017-11882, specifically related to the Equation Editor. The RTF structure includes OLE objects and an explicit trigger for Equation Editor activation. The embedded object data, when decoded, likely contains the malicious payload responsible for the exploit.

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_off0000125d.bin
12513a1219add4c75e353f2df98b82a9a7e43b3bf95305773969c927300872da		 rtf-objdata-decoded RTF \objdata at offset 0x125D 13645 bytes
objdata_01_off00008e13.bin
f8b5a628cca8052705075315f60d8870820cbef9e8e6e330f6fa8db735fb67b9		 rtf-objdata-decoded RTF \objdata at offset 0x8E13 275202 bytes

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