Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 0f5fe1c398ee437f…

MALICIOUS

RTF / .DOC

1.62 MB
MD5: 732b6af1b11bbfc3e17f4375c3d24b09 SHA-1: d8cfbfb47847a369299458cf59c1d8ae0148110d SHA-256: 0f5fe1c398ee437f2ff1059b9ea8d726bedabf44ff5b9348dfe17f721f2ade1b
260 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The RTF document contains critical heuristics indicating the exploitation of CVE-2017-11882 via Microsoft Equation Editor. This exploit is known to deliver a second-stage payload, likely a backdoor or infostealer. The presence of OLE object data and excessive hex data further supports the hiding of a malicious payload within the document.

Heuristics 6

  • 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.
  • Automatically linked OLE object high RTF_OBJAUTLINK
    RTF contains \objautlink — an automatically linked OLE object surface that can be updated or activated when Word opens the document.
  • \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 ~1696KB 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_off0000182e.bin
e19d66ff7b285fda13c2492664bafb92da630185d4b305ca0840ef17e63503e3		 rtf-objdata-decoded RTF \objdata at offset 0x182E 848395 bytes

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