Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 ec7fcaa97d56f7f7…

MALICIOUS

RTF / .DOC

2.09 MB
MD5: 6ba47017e264226322a4c0a55e84ec8e SHA-1: abcb6d52e28a0f3c02df63d2c4b416473b1a5349 SHA-256: ec7fcaa97d56f7f71a15047f3abc67619aa7b993f3ff1942f6b3ff43d8ffa390
180 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1059 Command and Scripting Interpreter T1211 // a bit too generic, let's be a reason for the same thing

The sample is an RTF document containing OLE objects designed to trigger CVE-2017-11882. The presence of RTF_EQUATION_EDITOR and CVE_2017_11882_ACTIVATION_RELATED heuristics indicates a high probability of the shellcode is embedded within the embedded OLE objects (objdata_00 and objdata_01).

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 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00001202.bin
c82bea6d1f811cdeeb304ed252c9de1d20f48bf87fea4494e6170e6ce02a92ee		 rtf-objdata-decoded RTF \objdata at offset 0x1202 27279 bytes
objdata_01_off0001cf2b.bin
2f05c0110283d6d66817dd760d3b8c77e60c29eaf269a6c8a7c9412afdda699d		 rtf-objdata-decoded RTF \objdata at offset 0x1CF2B 362865 bytes

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