Malicious RTF — malware analysis report

Static analysis result for SHA-256 5ce27e5abcee9c19…

MALICIOUS

RTF

2.62 MB
MD5: 998f7de66515446ec1eb5fc1353bdb98 SHA-1: f8e66af55cb639b31dee545c52028d6508b2a0ce SHA-256: 5ce27e5abcee9c19021f187e5e8ddc5886173e75d81e3921220e67bce1e0f2d8
180 Risk Score

Malware Insights

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

The RTF file contains embedded OLE objects and specifically triggers heuristics related to the Equation Editor vulnerability (CVE-2017-11882). This indicates the file is designed to exploit this vulnerability for client-side code execution. The presence of ".objupdate" further suggests an attempt to force OLE activation. Given the nature of the exploit, it is likely delivered as a spearphishing attachment.

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_off00000ded.bin
038c7ad115b030ae177c7f8f6149bb66202e2f2c9c8a48349bdf9166d217e3d8		 rtf-objdata-decoded RTF \objdata at offset 0xDED 63204 bytes
objdata_01_off0003c6e7.bin
bd688238fe4a81b93b1791e1c8455780aa3bc451293f8827d97ccbf101b8d65e		 rtf-objdata-decoded RTF \objdata at offset 0x3C6E7 555368 bytes

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