Malicious RTF — malware analysis report

Static analysis result for SHA-256 8751f13148ba51ee…

MALICIOUS

RTF

22.5 KB First seen: 2022-11-29
MD5: 0a298b66d8c6365a5753da3c818dce76 SHA-1: f15b1b924161c8194695b9c76fbc1891a8f46e29 SHA-256: 8751f13148ba51eeedb51fd71dfacd79a9c7f85bd41e67e80f1549fee3999508
140 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File T1059.005 Visual Basic

The RTF document contains an embedded OLE object with a specific ProgID indicative of the Equation Editor vulnerability (CVE-2017-11882). The \objupdate directive suggests that the embedded object is designed to be activated automatically upon opening the document, bypassing user interaction. This exploit is commonly used to download and execute a secondary payload, making the document a likely delivery mechanism for further malicious activity.

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_off00004087.bin
47eb7b4a9885fe8ff41f95a8d97c831ffc91135fb408d166c6fa304fa1fe572a
rtf-objdata-decoded RTF \objdata at offset 0x4087 1867 bytes