Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 b416c66b28f7f50e…

MALICIOUS

RTF / .DOC

120.9 KB First seen: 2023-10-23
MD5: cbef1fc77f8092b7f45d1ce80d6c8a08 SHA-1: e7a33bc33ea0eca8bfdae6a3e7f04707ef5a676c SHA-256: b416c66b28f7f50e2e31831f024c9554aa1e14530563e31dc254f209f5bbf3d4
140 Risk Score

Malware Insights

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

The file is an RTF document containing an embedded OLE object with an Equation Editor ProgID, a known exploit vector. The document also contains a lure instructing the user to 'Enable editing', indicating an attempt to trigger the exploit. The presence of ".objupdate" further suggests an attempt to automatically activate the embedded object. No scripts were extracted, and the document body content is benign financial advice, suggesting the exploit is the primary malicious function.

Heuristics 4

  • 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
  • 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_off000030a1.bin
545f44a427bf6b2100ccfa8c30560fadf9dcc8d094010536092e20b16fb0f89b
rtf-objdata-decoded RTF \objdata at offset 0x30A1 1855 bytes