Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 5af1b7b8ceda44f7…

MALICIOUS

RTF / .DOC

12.3 KB First seen: 2022-10-03
MD5: b6340efb709fcf61af6c4dbac8e78065 SHA-1: 54088de03c287b3a2d50dea47bf3a13e475e8765 SHA-256: 5af1b7b8ceda44f77e78d6683b854d4090e91239e988e002a78aea06e98a6b06
200 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File T1059.005 Visual Basic

The sample is an RTF document containing an embedded OLE object that exploits the Equation Editor vulnerability (CVE-2017-11882). The document body contains a lure instructing the user to 'Enable editing' to view the content, which is a common tactic to bypass macro security. The embedded OLE object is designed to execute arbitrary code upon activation, likely leading to a second-stage payload download or execution.

Heuristics 6

  • 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 1 \objdata section(s) — embedded OLE objects
  • Embedded OLE object medium RTF_OBJEMB
    RTF contains \objemb — embedded OLE object
  • Macro/content-enable lure medium SE_ENABLE_LURE
    Document instructs the user to enable macros or editing — a common technique used by malware droppers to bypass Office macro security settings

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off000005df.bin
3eba38643ec49996718d74e1337a93d7b3dbb35e8b0f90654e86c5977503012d		 rtf-objdata-decoded RTF \objdata at offset 0x5DF 2166 bytes

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