Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 8100bdc791ac1a44…

MALICIOUS

RTF / .DOC

49.9 KB First seen: 2023-09-07
MD5: 844ed467c9e0c8908079cb61ec5381f1 SHA-1: c83640a128c4869b402a1cb3e62c141aa8377737 SHA-256: 8100bdc791ac1a4417e49ad4628144b05c338ffc56ca9cb75623bf7af9c3929d
140 Risk Score

Malware Insights

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

The sample is an RTF document containing an embedded OLE object, specifically targeting the Equation Editor vulnerability. The document body discusses financial audits and includes a lure to 'enable editing', indicating a social engineering attempt to trick the user into activating the exploit. The presence of objdata and objupdate heuristics further confirms the exploitation of OLE object handling.

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_off000039b1.bin
f1270b00f7982a5efb93934294d719995aac365b4bfaf9d1373a921dcd2e2f1f
rtf-objdata-decoded RTF \objdata at offset 0x39B1 1539 bytes