Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 434a28fcf12ad8a9…

MALICIOUS

RTF / .DOC

23.5 KB
MD5: 80c4f031e31c6735bdbce132f199a673 SHA-1: cb87108ec80546dd51aada6966d0f0eb38e090de SHA-256: 434a28fcf12ad8a920683fa8d54ae5a7191edafd30af28f310306d6dd497cd12
180 Risk Score

Malware Insights

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

The sample is an RTF document that contains embedded OLE objects, specifically triggering heuristics related to Equation Editor. The presence of RTF_EQUATION_EDITOR and CVE_2017_11882_ACTIVATION_RELATED firings strongly indicates exploitation of the CVE-2017-11882 vulnerability. This vulnerability allows for arbitrary code execution when the embedded Equation Editor object is activated, likely leading to the download and 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_off00001572.bin
274f4303b84d9e5b92bfa61dd796034f757ea7ece113922e4521fcf126b13c55		 rtf-objdata-decoded RTF \objdata at offset 0x1572 1845 bytes

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