Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 ae490db307072b99…

MALICIOUS

RTF / .DOC

22.6 KB First seen: 2022-12-14
MD5: 941716cb419e619061c8d289aeca24aa SHA-1: 5577a3b0787142f825bef2445d72c1f46c50e579 SHA-256: ae490db307072b99d1d7bfe392dc54c9d2aeeee20b991242d8cbb45a96921204
140 Risk Score

Malware Insights

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

The sample is an RTF document containing an embedded OLE object with a split Equation Editor ProgID, indicating an attempt to exploit the Equation Editor vulnerability (CVE-2017-11882). The ".objupdate" directive forces OLE activation, and the "SE_ENABLE_LURE" heuristic suggests the document prompts the user to enable content. This combination strongly suggests a malicious document designed to exploit the Equation Editor vulnerability to execute arbitrary code, likely for a secondary payload download.

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_off0000450f.bin
388478904e0d558917b199f7ed792ce8833e914dd555adb3b3df7c36957571b5
rtf-objdata-decoded RTF \objdata at offset 0x450F 1773 bytes