Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 8211e35c2df7cabc…

MALICIOUS

RTF / .DOC

17.9 KB
MD5: e4ce95f03ab27b0d13b9072d1b0c2137 SHA-1: 8d69aba029dd8cd5d81e1b66c2924fc52faf0880 SHA-256: 8211e35c2df7cabc2715727576f75621a9640fe9f379564558a1c4298495f62e
180 Risk Score

Malware Insights

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

The RTF document contains an embedded OLE object that exploits the Equation Editor vulnerability (CVE-2017-11882). This vulnerability allows for the execution of arbitrary code, likely to download and run a secondary payload. The document body is heavily obfuscated and does not provide clear textual lures.

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_off00001d87.bin
fcc77072cc6eecc545a4973eceed2c85b3c186efb5b2194b9ac504289d9a7d5e
rtf-objdata-decoded RTF \objdata at offset 0x1D87 1569 bytes