Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 664f19503806894b…

MALICIOUS

RTF / .DOC

38.3 KB First seen: 2023-04-19
MD5: 669fd9cfcb64fa9def45ef397e602556 SHA-1: b20d3de1068830c0c9b0866bb3e2c28dff859676 SHA-256: 664f19503806894bd3f30b955345e148dab45b809243eb93858cbec0fa3c2d5d
140 Risk Score

Malware Insights

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

The sample is an RTF document containing an embedded OLE object, specifically targeting the Equation Editor vulnerability. The presence of \objupdate and a lure to 'Enable editing' strongly suggests an attempt to exploit this vulnerability to execute malicious code. The document body itself is a lure, presenting academic content to mask 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_off00004963.bin
ffccad05377ee194e89645356be16b5c8020b5094888fa2f4581608cdcc442ca
rtf-objdata-decoded RTF \objdata at offset 0x4963 1745 bytes