Malicious PDF — malware analysis report

Static analysis result for SHA-256 51481079d5ca4683…

MALICIOUS

PDF

81.8 KB Created: 2021-09-02 06:57:40 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-07
MD5: b61d0df9250be46b8edbd4236c96f4bf SHA-1: 16e3775a2e6f193f1ddf96ec4d74396ef8ba4d09 SHA-256: 51481079d5ca4683564f77439b1fa7303a0efd2b6d014b63981a8086882d5d8a
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF contains numerous links pointing to compromised WordPress sites, indicating a link farm designed to redirect users to malicious content. The ML classifier and ClamAV detection strongly suggest malicious intent, likely for phishing or malware distribution. No scripts were extracted, but the presence of external URIs and compromised CMS uploads points to a tactic of leveraging trusted-looking infrastructure for malicious purposes.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9985

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://inwebjor.ru/uplcv?utm_term=pins+and+needles+in+the+left+arm PDF link annotation
    • http://gennarimaq.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/16085d937981f0---89079595633.pdfIn PDF document text
    • https://kamhosting.nl/ckfinder/userfiles/files/84764695629.pdfIn PDF document text
    • https://chocoinmobiliario.com/wp-content/plugins/super-forms/uploads/php/files/3960ec0ee93fde6fa3fc38a41e6177a8/49571256081.pdfIn PDF document text
    • https://dedywiredja.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b318ace8777---83082721676.pdfIn PDF document text
    • https://www.denisonlandscaping.com/wp-content/plugins/formcraft/file-upload/server/content/files/16079ea9d6473b---gefire.pdfIn PDF document text
    • http://brenno-tojestto.pl/userfiles/file/gikunokofatigesan.pdfIn PDF document text
    • https://stefandes.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608b53d24e2a0---98069135454.pdfIn PDF document text
    • http://bukhatirhomes.com/userfiles/file/6100565024.pdfIn PDF document text
    • http://fewo-spreewald-schoetzigk.de/brandenburgtag/img/editor/file/23952192268.pdfIn PDF document text
    • http://hms31.ru/img/file/texeguxosatow.pdfIn PDF document text
    • http://baigeleather.com/userfiles/file/pabijarelapofupakezefati.pdfIn PDF document text
    • http://mai-colle.jp/userfiles/file/saluzafeliso.pdfIn PDF document text
    • http://vitaminyplus.eu/files/file/liniritijezuku.pdfIn PDF document text
    • http://agataklimowska.pl/userfiles/file/bepomofosiridogit.pdfIn PDF document text
    • https://www.nexidia.it/wp-content/plugins/super-forms/uploads/php/files/d01ffeb178a74390596e3345d173ca2a/xuvenibawemubixagul.pdfIn PDF document text
    • https://lanjutpt1.com/contents//files/88519114621.pdfIn PDF document text
    • http://vivatbacchus.hu/files/file/nulelofid.pdfIn PDF document text
    • https://www.sabiamente.es/wp-content/plugins/formcraft/file-upload/server/content/files/160a789b3da050---33151999779.pdfIn PDF document text
    • http://club-integra.ru/userfiles/file/55125112016.pdfIn PDF document text
    • https://vestol.bg/files/file/jigapotojajulikujede.pdfIn PDF document text
    • http://chocoenglish.com/_UploadFile/Images/file/7452369065.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_off0000dc9c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDC9C 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000f4b3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF4B3 10500 bytes
SHA-256: 39c3e841cc76c537294f8b91c4310b8fe4492571d02f8366f749708cd4f3536e
font_02_sfnt_off00010c4c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10C4C 17580 bytes
SHA-256: b399c9867dfc4bb63b8afc1fe4fa8fc5e0092c7a18f9a00b0afb893b3752785a