Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 da45997fb6f9d033…

MALICIOUS

RTF / .DOC

24.9 KB
MD5: 07ed71107ed941619f8f2dec7d65b049 SHA-1: 8712617ca351dcf32efc85256ebd916ccd7101b5 SHA-256: da45997fb6f9d033a3c0f2858553c353e3a1815f6eff9cabef82fd30b4ae5597
180 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File T1059.003 Windows Command Shell

The RTF document contains embedded OLE objects and specifically triggers the CVE-2017-11882 vulnerability related to Microsoft Equation Editor. This exploit allows for arbitrary code execution, likely to download and run a secondary payload. The presence of RTF_OBJDATA, RTF_OBJEMB, RTF_EQUATION_EDITOR, and RTF_OBJUPDATE heuristics strongly indicates 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_off00001c60.bin
b4f039493ab6f16784230fecaaad162a9b7d52dc8d08a836c584fedfe9fefe1b
rtf-objdata-decoded RTF \objdata at offset 0x1C60 1766 bytes