Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 3b1609ba0aaec094…

MALICIOUS

RTF / .DOC

37.5 KB First seen: 2023-05-24
MD5: bda882d3e2d315692d0b55b1fb7e381b SHA-1: 477c88d9915e362bfcdf30efc3faf7601e175e45 SHA-256: 3b1609ba0aaec0948237194283f85a68598b8fa104d4daaf56808624df7ede62
140 Risk Score

Malware Insights

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

The RTF document contains an embedded OLE object with a split Equation Editor ProgID, designed to be activated by the \objupdate directive. The document body includes a lure instructing the user to 'Enable editing' to view or edit the document, which would trigger the exploit. This indicates a likely exploit delivery mechanism targeting the Equation Editor vulnerability.

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_off0000516c.bin
421a99a55dea0e20960a6b8eb9fb31eba0b009ccec9e6559c7605a25eeb8ed2c
rtf-objdata-decoded RTF \objdata at offset 0x516C 1588 bytes