Malicious RTF — malware analysis report

Static analysis result for SHA-256 cbcbb25bf429bcbf…

MALICIOUS

RTF

698.9 KB Created: 2019-01-11 17:49:00 First seen: 2020-02-04
MD5: ae7e2c62f68b784c9d43fbf742217c09 SHA-1: 302a9009730112a4de0bc02406f414f124d2d828 SHA-256: cbcbb25bf429bcbf62bfd52318955f38a14057b14554b388fc59ceeb0a07177c
264 Risk Score

Malware Insights

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

The RTF document contains multiple indicators of malicious activity, including critical firings for RTF_EQUATION_EDITOR and CVE_2017_8759. These point to the exploitation of a known vulnerability in the Equation Editor component to achieve code execution. The presence of OLE objects and the ".objupdate" directive further suggest the activation of embedded malicious content. The ClamAV detection as Rtf.Dropper.Agent-7364424-0 confirms its malicious nature as a dropper.

Heuristics 8

  • 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-2017-8759 — 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.
  • ClamAV: Rtf.Dropper.Agent-7364424-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Rtf.Dropper.Agent-7364424-0
  • \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
  • Suspicious extracted artifact info 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.
  • 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 https://github.com/traviskaufman/node-lipsum In RTF body
    • http://ftp.ktug.or.kr/tex-archive/help/Catalogue/entries/lipsum.htmlIn RTF body
    • http://github.com/gsavage/lorem_ipsum/tree/masterIn RTF body
    • https://github.com/cerkit/LoremIpsum/In RTF body
    • http://www.layerhero.com/lorem-ipsum-generator/In RTF body
    • http://schemas.microsoft.com/office/word/2003/wordmlIn RTF body
    • https://www.lipsum.com/bannersIn RTF body
    • https://chrome.google.com/extensions/detail/jkkggolejkaoanbjnmkakgjcdcnpfkgiIn RTF body
    • https://addons.mozilla.org/en-US/firefox/addon/dummy-lipsum/In RTF body
    • http://code.google.com/p/pypsum/In RTF body
    • http://gtklipsum.sourceforge.net/In RTF body
    • http://groovyconsole.appspot.com/script/64002In RTF body
    • https://www.lipsum.com/privacy.pdfIn RTF body
    • http://bit.ly/2ssUlHmIn RTF body

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00068c79.bin rtf-objdata-decoded RTF \objdata at offset 0x68C79 8118 bytes
SHA-256: 2b85c99640a10e415b02263c55ddde6fac930a3d73fdf1e4a06996df3e395996
objdata_01_off0006cd49.bin rtf-objdata-decoded RTF \objdata at offset 0x6CD49 15856 bytes
SHA-256: 3f5c9a07a36e1835a9a20b846fef9e5ed90bfc28d0358f9effeab85615892d09
objdata_02_off00075152.bin rtf-objdata-decoded RTF \objdata at offset 0x75152 31062 bytes
SHA-256: 482c3d830713d2c1d71760ad90278a7cdce8b377c578a908eda7c574e363b3a6
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact entropy is 7.60, consistent with packed or encrypted content.

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