Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 590d166355ef9791…

MALICIOUS

RTF / .DOC

17.7 KB
MD5: 729c58a89b4d7d88de3733b5a2bba8dc SHA-1: 085a28957fefcd3d2cbc020af0aebabf27760bb8 SHA-256: 590d166355ef97918076a8e64b4a169a06f05df90311562dc5783191f80b4d31
180 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1059.001 PowerShell

The RTF file contains embedded OLE objects and specifically triggers the Equation Editor vulnerability (CVE-2017-11882). This vulnerability allows for the execution of arbitrary code when the document is opened. The embedded object data, when decoded, likely contains the exploit payload. The attack pattern is consistent with exploiting this known Microsoft Office vulnerability for initial 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_off00001550.bin
dfc4d27d277662afe7724b1a4c2f86855bf0ce2159114575197ce9262d2b47c1
rtf-objdata-decoded RTF \objdata at offset 0x1550 1655 bytes