Malicious RTF — malware analysis report

Static analysis result for SHA-256 603e67144f8ac8ad…

MALICIOUS

RTF

1.75 MB
MD5: 88112fa937025844e77c306a17444d4b SHA-1: f664118a0b5394c918a91a4bee86eef7d818bf69 SHA-256: 603e67144f8ac8ad03594bcbb739b74a91382b835f02b5252069eda5d30b480c
260 Risk Score

Malware Insights

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

The RTF document contains a critical heuristic firing for CVE_2017_11882_RELATED, indicating the exploitation of this known vulnerability through a malformed OLE object. The presence of RTF_OBJDATA, RTF_OBJAUTLINK, and RTF_EXCESSIVE_HEX heuristics further supports the embedding of a malicious OLE object. This object likely decodes and executes a second-stage payload, a common technique for initial execution.

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 ~1776KB 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_off000000a5.bin
af6baff802ab299646610cd9a1c00a3b02a2a68c8324074de564b26bf2ef9b6e		 rtf-objdata-decoded RTF \objdata at offset 0xA5 895719 bytes

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