Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 69c44e41e59c4e3d…

MALICIOUS

RTF / .DOC

28.7 KB First seen: 2023-03-27
MD5: 29c631a55a0a2839b8f4c0cd3cd7405b SHA-1: dc3ebea6f70afd37a72f2e79488354187808c95f SHA-256: 69c44e41e59c4e3d5c4dc5c36d59c3931c1a81bd905caaea6b75dbae6d1aa058
160 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 User Execution: Malicious File T1059.005 PowerShell

The RTF document contains an embedded OLE object with a split Equation Editor ProgID, indicating an attempt to exploit CVE-2017-11882. The ".objupdate" directive forces OLE activation, and the "SE_ENABLE_LURE" heuristic confirms the document instructs the user to enable editing. This combination strongly suggests the document is a dropper designed to exploit the Equation Editor vulnerability and execute a secondary payload upon user interaction.

Heuristics 5

  • 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
  • Embedded OLE object medium RTF_OBJEMB
    RTF contains \objemb — embedded OLE object
  • 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_off0000453a.bin
84a0c2f54eccfd250cc6af1deeee17e2ae62d1f8b4a6371abac12e3f235101cd
rtf-objdata-decoded RTF \objdata at offset 0x453A 1805 bytes