Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 83cd07ef3456aaef…

MALICIOUS

RTF / .DOC

21.2 KB
MD5: 9449f56413ec7de87124f2dbec474db4 SHA-1: a187fadcaba8727aee2dc5becfec90759864e8ba SHA-256: 83cd07ef3456aaef8a61a609d9e2aed4649703cb819872a69f552884a011bedf
180 Risk Score

Malware Insights

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

The RTF file contains embedded OLE object data and specifically triggers the CVE-2017-11882 vulnerability through the Equation Editor. This exploit allows for the execution of arbitrary code, 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_off00001cde.bin
e4bf453f1a6f2680d540a0ff891005d0a8b7b1c0c7d779b354468c7118e23459
rtf-objdata-decoded RTF \objdata at offset 0x1CDE 1859 bytes