Malicious PDF — malware analysis report

Static analysis result for SHA-256 51ca8c4a4e0f9e8b…

MALICIOUS

PDF

82.9 KB Created: 2021-09-20 13:28:12 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: 18d4f9eeb7d02a7ad82963d928151c50 SHA-1: 8bc61ae48c257cdb5c5146cc2e469c93a2d657d2 SHA-256: 51ca8c4a4e0f9e8b4f6859d506792a64670a5c3a335bc76460d6739cea0b313b
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file contains numerous embedded URLs, many of which point to compromised websites or link farms, indicating a phishing or malware distribution attempt. The ML classifier and ClamAV detection strongly suggest malicious intent. While no scripts were directly extracted, the PDF structure and embedded links are indicative of a malicious document designed to lure users to external sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • PDF link farm points to compromised-WordPress upload storage medium PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM
    PDF contains multiple clickable links, across many distinct hosts, whose targets are random-slug files parked in the upload directories of vulnerable WordPress form plugins (FormCraft, Super Forms). This is the hallmark of the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains hosted on compromised sites. The PDF itself carries no exploit — the risk is the linked destinations.
  • Small PDF is a non-clustered link farm on disposable hosting medium PDF_SEO_DISPOSABLE_LINK_FARM
    Small PDF contains many clickable external PDF links spread thin across many distinct hosts (no single dominant host), corroborated by a utm_term SEO-redirector link and/or links parked on free/disposable content hosts. This is the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains, rather than a normal document citation pattern. The PDF itself carries no exploit — the risk is the linked destinations.
  • External URI info PDF_URI
    PDF contains an external URL action
  • Object number defined twice with different bodies info PDF_DUPLICATE_OBJ_BODY_INCREMENTAL
    The same indirect object (N G) is defined more than once with different body bytes. First-wins and last-wins readers will resolve different content, which is a parser-confusion shape used by targeted PDFs. Body-only differences are common in benign incremental updates, so severity is raised only when the duplicate carries active content.
  • 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://cructi.ru/uplcv?utm_term=nitro+pro+8+64+bit PDF link annotation
    • http://www.uppld.org/wp-content/plugins/formcraft/file-upload/server/content/files/1613e2c547d504---zanezorirawudamuze.pdfIn PDF document text
    • http://gazetavk.ru/img/file/gojutavovabutexavuwom.pdfIn PDF document text
    • http://cambridgekapurthala.com/damana/userfiles/file/84441466945.pdfIn PDF document text
    • https://asiantms.com/ckfinder/userfiles/files/zenakivani.pdfIn PDF document text
    • https://nolimitscenter.be/peausitive/images/FCKeditor/file/tivowonaros.pdfIn PDF document text
    • https://vico-immobilien.com/ckfinder/userfiles/files/menevisar.pdfIn PDF document text
    • http://erdbau-rauch.at/79137760736.pdfIn PDF document text
    • https://semangkamerah.com/contents/files/vevonurewix.pdfIn PDF document text
    • http://taispacedesign.com/upload/files/81046865277.pdfIn PDF document text
    • http://www.nbrownies.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/16143a0b24c976---65041553849.pdfIn PDF document text
    • http://art-wonders.com/ckeditor/ckfinder/core/connector/php/uploads/files/86149605443.pdfIn PDF document text
    • https://rimi.sk/userfiles/file/jerasajajawepadejufeda.pdfIn PDF document text
    • http://www.propper-droppers.nl/files/file/77248437825.pdfIn PDF document text
    • http://hanasushimenifee.com/uploads/files/fiwasatavilukevowutotup.pdfIn PDF document text
    • http://lukasikgroup.pl/Image/files/rotugoxuxawewixinowumuba.pdfIn PDF document text
    • http://www.danvillern.com/wp-content/plugins/super-forms/uploads/php/files/c8d6e6aee8665083e12829ca28a63c6d/vinozudazuvokonetotin.pdfIn PDF document text
    • http://twozonechickenlasvegas.com/uploads/files/lapemanomanokima.pdfIn PDF document text
    • http://hastensandbreakfast.nl/userfiles/file/35967245294.pdfIn PDF document text
    • http://daeryuhealthcare.com/ckupload/files/55597938237.pdfIn PDF document text
    • https://ketgate.eu/wp-content/plugins/super-forms/uploads/php/files/7b5c034b228ab629cbbc43abc10cd004/dusofutukedijuwafikuboluf.pdfIn PDF document text
    • https://pmsp-me.com/userfiles/files/38217563650.pdfIn PDF document text
    • http://adriennemason.com/assets/files/sowimibamatonokevoporarox.pdfIn PDF document text
    • http://iranjobex.com/cache/fck_files/file/6462563408.pdfIn PDF document text
    • https://sma-dfgg.org/site/admin/file/vogotagirinawivozim.pdfIn PDF document text
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#In PDF document text
    • http://purl.org/dc/elements/1.1/In PDF document text
    • http://ns.adobe.com/pdf/1.3/In PDF document text
    • http://ns.adobe.com/xap/1.0/In PDF document text
    • http://ns.adobe.com/xap/1.0/mm/In PDF document text
    • http://ns.adobe.com/xap/1.0/rights/In PDF document text
    • http://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000e01c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE01C 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000f833.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF833 10204 bytes
SHA-256: d19bd43b5c005a778b5c4c2b7fcab63fdcd1db6013c28887c6041c7d493c0f4a
font_02_sfnt_off00010efd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10EFD 18172 bytes
SHA-256: f29ce65e058499f4aa873754ec977fe3ba08d99e6a8885044c5f9ff72785e484

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