Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 358f2a778fa197fc…

MALICIOUS

RTF / .DOC

14.5 KB
MD5: 7c75c42816ba9bbbdf663b3d49d6a96a SHA-1: 1a9be550cafb37e73d3e88cfd8a46554dcc22c95 SHA-256: 358f2a778fa197fc3b032f0b85542b882f681e38c4156881874d66fc2bf2bcb0
180 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1068 T1585.002 T1585.002 Malicious File

The sample is an RTF document containing a specially crafted OLE object targeting CVE-2017-11882. The presence of RTF_EQUATION_EDITOR and CVE_2017_11882_ACTIVATION_RELATED heuristics indicate the exploitation of the Microsoft Equation Editor vulnerability to achieve remote code execution.

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_off00000a11.bin
829f8540658c54f332d327b01853af9a68b3cd73e880f303c4f2e30a84f4df34
rtf-objdata-decoded RTF \objdata at offset 0xA11 2010 bytes