Malicious RTF — malware analysis report

Static analysis result for SHA-256 c4f43419d665b772…

MALICIOUS

RTF

128.8 KB Created: 2019-07-25 13:36:00 First seen: 2019-11-20
MD5: 9baad36c57925f7e9e952718c6daefb6 SHA-1: 3efc985d07472d793197f2f843d2f4cd039dfb37 SHA-256: c4f43419d665b7725386c75dea9bc8b1b4c87c1184a4b3596f64980fc08023bf
362 Risk Score

Malware Insights

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

The RTF file contains embedded OLE objects and specifically triggers critical heuristics for CVE-2017-11882 and CVE-2017-8759, indicating exploitation of Equation Editor vulnerabilities. The presence of shellcode API strings and a shellcode candidate region within an extracted artifact further supports the execution of arbitrary code. This suggests the file is designed to exploit these vulnerabilities to download and execute a secondary payload.

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
  • Equation Editor Ole10Native payload — CVE-2017-11882 likely critical CVE likely CVE_2017_11882_EQUATION_OLE10NATIVE
    RTF decodes to an activated Microsoft Equation 3.0 OLE storage whose payload is a high-entropy Ole10Native stream rather than normal Equation Native/MTEF data. This is a weaponized Equation Editor RCE delivery shape consistent with CVE-2017-11882/CVE-2018-0802.
  • CVE-2017-8759 — MSXML SAX OLE activation critical CVE likely CVE_2017_8759
    RTF contains a hex-encoded OLE1 object for Msxml2.SAXXMLReader.6.0 followed by an embedded OLE compound document, and the document requests OLE activation. This matches the RTF staging shape used for CVE-2017-8759 SOAP/WSDL parser code injection.
  • Ole10Native stream in RTF OLE object high CVE related RTF_OLE10NATIVE_STREAM
    RTF contains an embedded OLE object with an Ole10Native stream. This is a strong payload-container signal and is related to Word/OLE exploit delivery, but it is not specific enough on its own to assign a CVE.
  • 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.
  • \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 In RTF body
    • https://bit.ly/2PhS93PIn RTF body

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off0001bc48.bin rtf-objdata-decoded RTF \objdata at offset 0x1BC48 3622 bytes
SHA-256: 1a8b7b9d3e97abfcb9ba864e9c9a0ade81376c477470f5ea12cfe2e596a9da6c
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Static shellcode analysis recovered URL(s): https://bit.ly/2PhS93P Static shellcode analysis found candidate code region(s). Indicators: SC_STR_LOADLIBRARY, SC_STR_URLDOWNLOAD, SC_PEB_ACCESS Static shellcode analysis recovered API/import strings: LoadLibraryA, GetProcAddress, URLDownloadToFileA, ExitProcess

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