Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 904777c7fe7ac304…

MALICIOUS

RTF / .DOC

16.8 KB First seen: 2022-09-30
MD5: 56c375d29ab571937bfa1195602c5f25 SHA-1: 8a608be2a0c0f8ad0f6f96d0d45faa346bfb501c SHA-256: 904777c7fe7ac3045212bb0d9edce560d2fe56704db86faf38c2f2c6270f6f82
140 Risk Score

Malware Insights

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

The file is an RTF document that exploits the Equation Editor vulnerability. It contains an OLE object and uses an objupdate directive to force activation, indicating an attempt to execute embedded malicious content. The document body explicitly instructs the user to 'Enable editing' and mentions it was created in an 'earlier version microsoft office word', serving as a lure to bypass security measures.

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_off00001d90.bin
42d6121ee35ff5248beef243bbd82657ad02bd8f3b6b99f3aabb417345917bb0
rtf-objdata-decoded RTF \objdata at offset 0x1D90 1852 bytes