Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 6faeca079f4bada6…

MALICIOUS

RTF / .DOC

5.59 MB First seen: 2022-08-09
MD5: 0736641a179fa3aaa63d511c5e930a4a SHA-1: 84ccc8470f7c26eae270bf053e5aa7cd4f6bbedc SHA-256: 6faeca079f4bada698750fc2de9a9dc000c23a7786877accea5be7121924185b
220 Risk Score

Malware Insights

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

The sample is an RTF document containing a critical heuristic indicating exploitation of CVE-2017-11882 via the Equation Editor. The presence of OLE object data and excessive hex-encoded data further suggests a hidden payload. The document body is heavily obfuscated and does not provide clear textual lures, but the exploit itself is the primary indicator of malicious intent, likely to download and execute a secondary payload.

Heuristics 5

  • Equation Editor OLE1 native payload — CVE-2017-11882 related critical CVE related CVE_2017_11882_RELATED
    RTF decodes to an OLE1 Equation.3 embedded object whose native data is large and payload-like, and \objupdate requests automatic activation. This is the delivery shape used by Equation Editor RCE documents such as CVE-2017-11882/CVE-2018-0802, but the malformed MTEF record needed for exact 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.
  • Large hex data blocks in OLE object high RTF_EXCESSIVE_HEX
    RTF contains ~5858KB of hex-encoded data inside \objdata sections — may hide a payload
  • OLE object data medium RTF_OBJDATA
    RTF contains 2 \objdata section(s) — embedded OLE objects

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00000b07.bin
aeb5d868ea37b519aa9a82fb320f32b1ee944d5a3b84a851dbd9761953cbfbc1		 rtf-objdata-decoded RTF \objdata at offset 0xB07 2929191 bytes

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