Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 86a89e50316f1ea9…

MALICIOUS

RTF / .DOC

13.2 KB
MD5: 6c38309707bee74fc2e79531573097be SHA-1: 91d9da7e8210713a0c0a6af75dcf1016bb648731 SHA-256: 86a89e50316f1ea9b049e6872e2469944929003e4d166332493b83e1c1db5fad
180 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The RTF document contains heuristics indicating the exploitation of CVE-2017-11882 through an embedded OLE object, specifically related to the Equation Editor. This vulnerability is commonly used to achieve arbitrary code execution on the victim's machine. The presence of RTF_OBJDATA, RTF_OBJEMB, RTF_EQUATION_EDITOR, and RTF_OBJUPDATE heuristics strongly suggests this attack vector.

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_off000015b0.bin
ac9286676a4d859b449f134df006d1395667f0cef2f57f01de4cc27fb62169cf
rtf-objdata-decoded RTF \objdata at offset 0x15B0 1910 bytes