Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 3bf405e63323ac17…

MALICIOUS

RTF / .DOC

18.3 KB
MD5: fea1f312f1a030c13152b3ec3f4d1c17 SHA-1: a5cf28788f0024cbcaae005118d2af8187c17d87 SHA-256: 3bf405e63323ac175eca7a3804f9ef2a81fef23e5d563f0ba8e8e4f24b64168d
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, specifically triggering a critical heuristic for the Equation Editor. High-confidence firings indicate exploitation of CVE-2017-11882, which is known to allow arbitrary code execution. The presence of the 'EQUaTioN.3' ProgID further supports this. The exploit likely leads to the execution of a second-stage payload.

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_off00001f93.bin
19487dbf950a30adbe5360edbbcd957a3cf80938a77f191625200e3689fcecab
rtf-objdata-decoded RTF \objdata at offset 0x1F93 1738 bytes