Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 cb03ee017dd588d0…

MALICIOUS

RTF / .DOC

44.4 KB First seen: 2023-05-12
MD5: bfb4ee7c6f7c0a613917f8b79862064f SHA-1: 6d133ff25411242325ea66fcd6fa6919d9bc32f2 SHA-256: cb03ee017dd588d096cb96546982c8e1dd10ccfb32f56e3d8e3867b049091585
140 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File T1059.005 Visual Basic

The sample is an RTF document that contains embedded OLE object data, specifically targeting the Equation Editor vulnerability. The ".objupdate" directive indicates an attempt to automatically activate the embedded object upon opening, which is a common technique for exploiting this vulnerability. The document body contains a lure to enable editing, further supporting the malicious intent.

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_off000051af.bin
dbe01e93d4e1c174648de04ec5d159f27a56099a0e8bf40bc250c22538c62db5
rtf-objdata-decoded RTF \objdata at offset 0x51AF 2212 bytes