Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 12a527ecf3cdd651…

MALICIOUS

RTF / .DOC

69.5 KB
MD5: 31be22d61dea7b497432c5e99b17ca63 SHA-1: 1a5b5757703bb9e96ffcfa39cd5bbfd8e62893dd SHA-256: 12a527ecf3cdd651d019b393630ad1aeb83b63ef7efb2dbe92c1d3fcac2ad45f
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 CVE-2017-11882, a known vulnerability in Microsoft Equation Editor. This exploit is designed to execute arbitrary code upon activation, likely leading to the download and execution of a secondary payload. The presence of the 'EQUaTIoN.3' ProgID strongly indicates the use of this specific vulnerability.

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_off000005de.bin
323abcb98e1d79239d661b2536ec4f9eb0669fd79881e61ff941bfdf4b72ed0e
rtf-objdata-decoded RTF \objdata at offset 0x5DE 1686 bytes