Malicious RTF — malware analysis report

Static analysis result for SHA-256 02f90d2933fc9cb1…

MALICIOUS

RTF

229.1 KB Created: 2021-02-12 04:30:00
MD5: c3b677e557a9ae5f3121509ce7401357 SHA-1: 6c3c7e2dfabd0aae7ce59d2eddb9a38650f3fa53 SHA-256: 02f90d2933fc9cb1901c819c89c2cb96468e2af11103c587c247a2e822aae441
202 Risk Score

Malware Insights

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

The sample is an RTF document that contains an embedded OLE object, specifically targeting the Equation Editor. Heuristics indicate the use of \objupdate, which forces OLE activation, strongly suggesting exploitation of a known vulnerability like CVE-2018-0802. This exploit allows for client-side code execution, likely to download and run a secondary payload. The document body content appears benign, but the critical heuristics point to a malicious exploit.

Heuristics 6

  • Equation Editor CLSID critical RTF_EQUATION_EDITOR
    Equation Editor OLE CLSID found inside an OLE object — exploited by CVE-2017-11882 / CVE-2018-0802 / CVE-2018-0798
  • ClamAV: Rtf.Exploit.CVE_2018_0802-6825822-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Rtf.Exploit.CVE_2018_0802-6825822-0
  • \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
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://schemas.microsoft.com/office/word/2003/wordml

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00000106.bin
8bbbddaab38ec806db40fba8f14be497fa21d706dda03a7d9d7f79f4d49a0471
rtf-objdata-decoded RTF \objdata at offset 0x106 2492 bytes