Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 8c5196ab71948b50…

MALICIOUS

RTF / .DOC

29.5 KB First seen: 2023-03-30
MD5: 1d885d248d97db197cbf33f0378d552e SHA-1: 382bf7ab69aa792cb9c9be30dc2e1b57f5b46a7f SHA-256: 8c5196ab71948b50f40dec9109a01ace94593cc5d606588814b21cbfdcce5c17
160 Risk Score

Malware Insights

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

The RTF document contains an embedded OLE object and an Equation Editor ProgID, indicating an attempt to exploit a known vulnerability. The document body includes a lure to 'Enable editing', which is a common tactic to bypass macro security settings and activate malicious content. The presence of RTF_OBJDATA, RTF_OBJEMB, and RTF_OBJUPDATE heuristics further supports the exploitation of embedded objects.

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_off000049f5.bin
b9667c7e88ea64e371208fc12246b7bde61fc31af8fe472d154cddccc09f75c0
rtf-objdata-decoded RTF \objdata at offset 0x49F5 1412 bytes