Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 fc8d1f8eb16b7449…

MALICIOUS

RTF / .DOC

72.6 KB First seen: 2023-10-12
MD5: da6926c9e16d0943570d5e5e9fcb4e9e SHA-1: 3a25df2cc3ab727e49b8e7677e1a2974b80d4a60 SHA-256: fc8d1f8eb16b7449dc21d2f540660d1ee5bed946e8cef749a50a6220c74ac921
140 Risk Score

Malware Insights

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

The file is an RTF document containing an embedded OLE object that exploits a vulnerability in the Equation Editor. The document body includes a lure instructing the user to 'Enable editing', which is a common tactic for macro-based malware droppers. The presence of RTF_EQUATION_EDITOR and RTF_OBJUPDATE heuristics strongly indicates an exploit targeting this component.

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_off00003fbc.bin
165afaac1334a763200ca0fcfe876ba29d59ab3e503c1e7dd078a692acaf5609
rtf-objdata-decoded RTF \objdata at offset 0x3FBC 1630 bytes