Malicious PDF — malware analysis report

Static analysis result for SHA-256 c937fb65a448d721…

MALICIOUS

PDF

82.3 KB Created: 2021-09-04 10:26:32 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-05
MD5: f3fb5983e86840b40376a062798fac45 SHA-1: 331bd73004e8f2e022094ee1cf92e60890b7cace SHA-256: c937fb65a448d721fc7c6244f8265e9434460df92c4044ecb36d42bb2c96d461
196 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file is a PDF containing a large number of external links, many pointing to compromised WordPress sites. This pattern is indicative of a phishing campaign or a distribution point for malicious payloads. The ClamAV detection and ML classifier further support its malicious nature. No scripts were extracted, but the link farm structure is a common tactic for initial access.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

Heuristics 7

  • 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 to algorithmically-generated URL high PDF_RANDOM_URL_LINK
    PDF contains a clickable HTTP(S) link whose host looks algorithmically generated (pronounceable-random labels) and whose path/query carries a long high-entropy token. This is the randomized-redirector pattern of malspam phishing lures — the visible document is only a prompt — not a PDF parser vulnerability.
  • 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 http://nirmalamathachurch.org/cms_uploads/image/file/81293871366.pdf In PDF document text
    • https://khonggiansangtao.com/platformecom/img/upload/file/22836202104.pdfIn PDF document text
    • http://pxmonastery.org/CKEdit/upload/files/62085418875.pdfIn PDF document text
    • https://netpage.info/userfiles/file/devaziroperuzekeg.pdfIn PDF document text
    • https://sk-developers.com/wp-content/plugins/formcraft/file-upload/server/content/files/16126e912eca29---69480535278.pdfIn PDF document text
    • http://ednak.com/wp-content/plugins/formcraft/file-upload/server/content/files/160ba5718c90ab---tegefiwozulafinawelanuwi.pdfIn PDF document text
    • http://doublehappyvstheinfinitesadness.com/wp-content/plugins/formcraft/file-upload/server/content/files/160893a641379d---15990726257.pdfIn PDF document text
    • https://marblobath.com/app/webroot/img/files/sidurozesikelisomo.pdfIn PDF document text
    • https://boumqueur-edition.com/upload/fckeditor/file/1536894371.pdfIn PDF document text
    • http://bakefruit.com/uploads/files/202108132021297879.pdfIn PDF document text
    • http://gptools.net/userfiles/file/pojuripopobosafutixipix.pdfIn PDF document text
    • http://oprfhs70.com/clients/879438/File/pefunowamipolawekunixun.pdfIn PDF document text
    • https://www.traveltimevipp.com/wp-content/plugins/super-forms/uploads/php/files/736325616407b7b87624f2917c915137/rabavukumigeba.pdfIn PDF document text
    • http://training-solutions.ro/wp-content/plugins/formcraft/file-upload/server/content/files/160877ff7eddee---fogegovufobe.pdfIn PDF document text
    • https://xn--interpeas-r6a.es/upload/files/63732943685.pdfIn PDF document text
    • http://drinkandshrink.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/1612f1ffee919a---56338647356.pdfIn PDF document text
    • https://alubiasdetolosa.com/files/galeria/files/5845022336.pdfIn PDF document text
    • https://sportsht.com/userfiles/file/31087322592.pdfIn PDF document text
    • http://topspeed4wd.com/ckfinder/userfiles/files/82647380985.pdfIn PDF document text
    • https://patriot.ch/wp-content/plugins/super-forms/uploads/php/files/4ujpn2pop3evpob11uaaqn6e3d/24933372885.pdfIn PDF document text
    • http://npi-management.org/ressource/site-image/files/jakin.pdfIn PDF document text
    • https://blueridgelightingandcontrols.com/wp-content/plugins/super-forms/uploads/php/files/673b5cb5b406203ee0d5a5096aa379bc/kazosiburejexilobepolonu.pdfIn PDF document text
    • https://wpsqld.com.au/wp-content/plugins/super-forms/uploads/php/files/abc78edb077bd55c09481ba0644fd965/90865700302.pdfIn PDF document text
    • http://zzzwchem.com/upload/files/gufarojoxalov.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/DOqCt-cVA4I/uplcv?utm_term=introduction+to+machine+learning+with+python+pdf+freePDF link annotation
    • 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_off0000dc57.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDC57 11148 bytes
SHA-256: c7b3b67af13d9c67be86a42f2235fe2f2e32997d7ff87d97bd4ae05d64112942
font_01_sfnt_off0000f610.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF610 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00010e22.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10E22 17336 bytes
SHA-256: ea1596d867f44bb3e5e6872855292d703cb38a3b127864be92bfa57a3c3841c9

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