Malicious RTF — malware analysis report

Static analysis result for SHA-256 5be5d234f074ccd9…

MALICIOUS

RTF

258.8 KB Created: 2021-02-12 04:30:00
MD5: b6d0657bfc962bf8246ef3973db3115e SHA-1: 010ef19dd588bcaec011633365b1a7a769b2189b SHA-256: 5be5d234f074ccd9df2611cc73a47f73da4b52fee1b82a4ba6b2ff1aeeec6af4
142 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 triggering the CVE-2017-11882 vulnerability in Microsoft Equation Editor. This exploit is known to facilitate arbitrary code execution, which is likely used here to download and run a secondary malicious payload. The document body content appears benign, but the exploit is the primary indicator of malicious intent.

Heuristics 5

  • 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.
  • \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
66e92d48fb7083847a6a3d252b9d059af83f2c68a79ca4ec31734db0f18c631f
rtf-objdata-decoded RTF \objdata at offset 0x106 2877 bytes