Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 ac1e94789e8981ee…

MALICIOUS

RTF / .DOC

860.8 KB First seen: 2022-09-19
MD5: 5b4d9efc505b43d0bb3caafa04d2b6d0 SHA-1: 5105dd958278ac70232ec2276636f4bcd46a39b8 SHA-256: ac1e94789e8981ee3b9072177d1479dd1d6bc1bc8afccfdb3b3295afb8445080
180 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File

The RTF document contains an embedded OLE object that exploits CVE-2017-11882 via the Equation Editor. This exploit is designed to execute arbitrary code, likely a malicious script as indicated by the heuristic firings. The embedded object's ProgID 'Equation.3' is a strong indicator 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 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off0000129e.bin
0ab1cba82b5327f0d7771809e5810d7e9f9c315e8bf2f9a8f3d7ce3dadd69b15		 rtf-objdata-decoded RTF \objdata at offset 0x129E 81452 bytes
objdata_01_off0002f074.bin
8241f500b6f66c0010a61e3e66b293b7e5e246b297d9c6a44403288dc5895294		 rtf-objdata-decoded RTF \objdata at offset 0x2F074 140710 bytes

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