Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 49daa059670f6f91…

MALICIOUS

RTF / .DOC

27.8 KB First seen: 2023-06-15
MD5: e65e27e0c4a8ea50e36985a26b33b672 SHA-1: 47829286b8ab097fa79bf01bd6e8382f321843e3 SHA-256: 49daa059670f6f912d4754a24773df9326ef649f419ca2aaebcbee39e4b925e1
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, a known exploit vector. The \objupdate directive forces OLE activation, and the document body contains a lure instructing the user to 'Enable editing'. This combination strongly suggests an attempt 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_off0000517d.bin
53e5207196de82bbe8a44fc88efe3ae0bec0d9919fc45dd14746a35e2b1965fc
rtf-objdata-decoded RTF \objdata at offset 0x517D 1364 bytes