Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 258666b42a8321ce…

MALICIOUS

RTF / .DOC

30.3 KB First seen: 2023-03-22
MD5: 14ec616e9d4790509116ef8d38702b24 SHA-1: 753fb67d5c988010094c58c5455f894954a6b23d SHA-256: 258666b42a8321ce521094e20bbb630bd27a8a2c96afdb2969aa5cf132fe8b26
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 an Equation Editor ProgID, triggered by \objupdate, which is a known technique for exploiting vulnerabilities like CVE-2017-11882. The document body includes a lure instructing the user to 'Enable editing', indicating a social engineering attempt to bypass macro security settings and execute the embedded exploit.

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_off00005a99.bin
bca05b2db644093082d4fb2e856cf197c7cf5818c94f7a5b9ee698fe1d318228
rtf-objdata-decoded RTF \objdata at offset 0x5A99 1422 bytes