Malicious RTF — malware analysis report

Static analysis result for SHA-256 c33a349c74a7b158…

MALICIOUS

RTF

238.0 KB Authoring application: Riched20 6.3.9600 First seen: 2018-07-27
MD5: c6a8b7a0b04d445e3609404e307aa81b SHA-1: 7e9053e0d334376814ac6560a2bf26fb8606a216 SHA-256: c33a349c74a7b15833169189cfc31fdb9c7bf25212a113ce363fbca4bd13bd1d
260 Risk Score

Malware Insights

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

The RTF file contains an embedded OLE object that exploits CVE-2017-11882 via the Equation Editor. This vulnerability allows for the execution of arbitrary code, likely to download and run a secondary payload. The file is identified as malicious by ClamAV with a specific signature for this exploit.

Heuristics 6

  • Equation Editor CLSID critical CVE likely RTF_EQUATION_EDITOR
    Equation Editor OLE CLSID found inside an OLE object — exploited by CVE-2017-11882 / CVE-2018-0802 / CVE-2018-0798
  • CVE-2017-11882 — Equation Editor FONT record overflow critical CVE likely CVE_2017_11882
    Equation Editor MTEF contains an overlong FONT typeface field, the vulnerable copy primitive for CVE-2017-11882. This is stronger evidence than the Equation Editor CLSID alone because it identifies the malformed record that drives code execution in EQNEDT32.EXE.
  • ClamAV: Rtf.Exploit.CVE_2017_11882-6584355-1 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Rtf.Exploit.CVE_2017_11882-6584355-1
  • \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 1 \objdata section(s) — embedded OLE objects
  • Embedded OLE object medium RTF_OBJEMB
    RTF contains \objemb — embedded OLE object

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off000000fe.bin rtf-objdata-decoded RTF \objdata at offset 0xFE 4578 bytes
SHA-256: dc0ab328def6a3ec6eda544af01a0c51f54b7d09a398fad695c3851ccf398d98

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