Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 1c1ba54ce1e7e46e…

MALICIOUS

RTF / .DOC

15.7 KB
MD5: f59e0d727b69fe6317a412ca6a35248a SHA-1: 6745002e6fdf4d159dc526595ed77a69712dce01 SHA-256: 1c1ba54ce1e7e46ec834d90d07e08213a24516a202df39e00706d0e3c80f5d0d
180 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution

The RTF file contains embedded OLE object data, specifically related to Microsoft Equation Editor. Heuristics indicate the exploitation of CVE-2017-11882, which is a known vulnerability allowing for arbitrary code execution when the embedded object is activated. The ".objupdate" directive forces this activation, leading to the execution of malicious code.

Heuristics 5

  • Obfuscated Equation Editor ProgID + activation critical CVE related RTF_EQUATION_EDITOR
    RTF decodes to an Equation.3 ProgID from top-level \objdata hex after nested RTF junk groups are ignored, and the document also contains \objemb plus \objupdate activation. This is an obfuscated Equation Editor exploit surface associated with CVE-2017-11882 / CVE-2018-0802 families, but no exact malformed MTEF CVE primitive was recovered from this object.
  • 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.
  • \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_off00001d42.bin
dee3a617b018dd9c5710f0dd31d096d2d541d6051659d5ad89908d0f69672823		 rtf-objdata-decoded RTF \objdata at offset 0x1D42 1380 bytes

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