Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 ad404bad3ebfc9b0…

MALICIOUS

RTF / .DOC

166.2 KB First seen: 2021-09-23
MD5: 58179d86faa0963ecbdd7ad991f9b576 SHA-1: 9ac7203e61eb2b615beb858a123fbbe2abf895b6 SHA-256: ad404bad3ebfc9b0f0555932b9af44882b7699fd785bf165e138c358a7643352
142 Risk Score

Malware Insights

MITRE ATT&CK
T1204.002 Malicious File T1559.001 Component Object Model T1059.003 Windows Command Shell

The RTF document contains embedded OLE objects, specifically triggering the CVE-2017-11882 vulnerability through an Equation Editor font record overflow. This exploit is designed to activate the OLE object, which in turn downloads and executes a payload from the URL http://79.134.225.85:89/uploads/putty1.exe. The presence of the exploit and the download URL strongly indicate a malicious intent to deliver a secondary payload.

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 3 \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://79.134.225.85:89/uploads/putty1.exe

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off000000dc.bin
a7f55ebe22c7e0cf18446114d7041a847eca62f5d8835b1b4d8aec7ef28b1273
rtf-objdata-decoded RTF \objdata at offset 0xDC 16130 bytes