Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 5f36105c6c62a071…

MALICIOUS

RTF / .DOC

30.0 KB First seen: 2022-12-08
MD5: d15f571633b3bc3e1512a7c3d9ff3424 SHA-1: e3a3b2c81a8ebab816baed1582dcd662c2ea2751 SHA-256: 5f36105c6c62a071be7068bebdba5818e9199b6e1678de32b2c107498ab7f5ae
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 specific Equation Editor ProgID, and an \objupdate directive that forces OLE activation. This strongly suggests an attempt to exploit a known vulnerability in the Equation Editor component of Microsoft Office. The document body includes a lure to 'Enable editing', which is a common tactic for macro-based malware droppers to bypass security settings and execute malicious code.

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_off000043d9.bin
4b9e06692d2a785e1417d0b4048bf1642b31329876f21b8842def4591809df9b
rtf-objdata-decoded RTF \objdata at offset 0x43D9 2050 bytes