Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 4138434cbc206b77…

MALICIOUS

RTF / .DOC

8.3 KB
MD5: b50ecd05e33c6fd8f679d10f1c39842c SHA-1: d1534c5e62ad04270055447a2d191e2b2137ea73 SHA-256: 4138434cbc206b7784f77de845b2614a046b50be1ad47f3bd91c4622952aabf7
180 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1559.002 Component Object Model Hijacking

The RTF file contains embedded OLE objects and specifically triggers the CVE-2017-11882 vulnerability related to Equation Editor. This exploit allows for arbitrary code execution upon opening the document. No further stages or specific IOCs were identified in the static analysis.

Heuristics 5

  • Equation Editor activation — CVE-2017-11882 related high CVE related CVE_2017_11882_ACTIVATION_RELATED
    RTF decodes to an Equation.3 ProgID and requests OLE activation with \objemb plus \objupdate. This reaches the legacy Equation Editor attack surface used by CVE-2017-11882/CVE-2018-0802 documents, but the malformed MTEF/native payload needed for stronger attribution was not recovered.
  • 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 2 \objdata section(s) — embedded OLE objects
  • Embedded OLE object medium RTF_OBJEMB
    RTF contains \objemb — embedded OLE object

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00000d1d.bin
fc2fb5bf22888976775f9095ebfc7831f8a13f48ca827ca5b2edef8ad647becc
rtf-objdata-decoded RTF \objdata at offset 0xD1D 1882 bytes