Malicious RTF — malware analysis report

Static analysis result for SHA-256 f443d54ed21c034b…

MALICIOUS

RTF

1.05 MB First seen: 2022-08-31
MD5: 067208a716e65c2c5018064d00078ac5 SHA-1: f5bd4fba468d7119f3dda5d4e5c9d6b2f3f9ce4b SHA-256: f443d54ed21c034b61c6e71a4f4705f33684d36b5784aa997461a88e99dc5202
180 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File

The RTF document contains embedded OLE objects, specifically triggering the CVE-2017-11882 vulnerability related to Equation Editor. This exploit is designed to execute arbitrary code, likely a second-stage payload. The presence of OLE objects and the specific Equation Editor exploit strongly indicate a malicious document intended for exploitation.

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_off00001291.bin
20c3798c91d376e3d19cfcea8f12fc47335446be3f00ef64246d49ed146b0eb3		 rtf-objdata-decoded RTF \objdata at offset 0x1291 76405 bytes
objdata_01_off0002c8ec.bin
e1fc1a4c0e67e69e3fb71023b7446271b7980a05bfadf3f1c66142aaf4530e1c		 rtf-objdata-decoded RTF \objdata at offset 0x2C8EC 187172 bytes

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