Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 ddaa06260a5ae0fd…

MALICIOUS

RTF / .DOC

863.0 KB First seen: 2022-09-29
MD5: 0b587ac0ff2ce61c7c076690f44cb9df SHA-1: 696ff20245808836665d56966561ec5d20f07f30 SHA-256: ddaa06260a5ae0fd944b528288449fda16b5f3206c8e12c559d7be2088b9bf16
180 Risk Score

Malware Insights

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

The sample is an RTF document that leverages the Equation Editor vulnerability (CVE-2017-11882) to embed and activate an OLE object. This technique is commonly used to download and execute arbitrary code. The embedded OLE object likely contains a script or executable designed to perform further malicious actions, such as establishing persistence or downloading additional malware.

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
23ff1d10898aed079b89ba1db7cb064bc4738d451776f6a353de42e75ad9d78e		 rtf-objdata-decoded RTF \objdata at offset 0x129E 81503 bytes
objdata_01_off0002f0da.bin
3191c7b669a99e6dbec6e45083f1ba3cae1925f2a91f1d3c51265214befb2f16		 rtf-objdata-decoded RTF \objdata at offset 0x2F0DA 141152 bytes

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