Malicious PDF — malware analysis report

Static analysis result for SHA-256 83c5baccc3190d8e…

MALICIOUS

PDF

69.2 KB Created: 2021-08-28 01:10:58 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-17
MD5: f3f21da5115bd49a1aa6c64f26ec7c77 SHA-1: 9512b272d0a947e54062de49c2981f57b4b56b06 SHA-256: 83c5baccc3190d8ebb88bed3fa4022312aa9bdfb45a97a609585f6a218f4bc1b
96 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, which in turn host more PDF files. This structure suggests a link farm designed to distribute malicious content or lead users to phishing pages. The ML classifier strongly indicated maliciousness, and the presence of multiple link farm heuristics supports this assessment.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9971

Heuristics 5

  • 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://afd.me.uk/wp-content/plugins/super-forms/uploads/php/files/9nql7np3qpsj0rbdc8udtonc8t/42017732130.pdf In PDF document text
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a2cdd1416f9---tasemixugolerut.pdfIn PDF document text
    • https://jiptv.nl/wp-content/plugins/super-forms/uploads/php/files/ipv6v0keakj3m80kkf63i4d7oj/50431631201.pdfIn PDF document text
    • http://jeugdopdewetenschapsagenda.nl/wp-content/plugins/formcraft/file-upload/server/content/files/160a0f8e920bf8---gibibefi.pdfIn PDF document text
    • http://www.yourhealthyourchoice.org/wp-content/plugins/formcraft/file-upload/server/content/files/1607c97792a98c---39719802682.pdfIn PDF document text
    • http://jts-electrical.co.uk/ckfinder/userfiles/files/pinajesowakebasafa.pdfIn PDF document text
    • http://busankid.com/webfiles/board/file///38850310017.pdfIn PDF document text
    • http://chatsworth72.com/clients/5/53/532ec3c8dc0e95779814939736d4df6d/File/14438034557.pdfIn PDF document text
    • http://186086.com/upload/files/wimovomonipefosur.pdfIn PDF document text
    • https://www.hagensmarketing.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a5928e251c9---miwimitofijonidijawer.pdfIn PDF document text
    • http://www.timtransportes.com/home/wp-content/plugins/formcraft/file-upload/server/content/files/16072355c8296c---84266634767.pdfIn PDF document text
    • https://esportenerd.com/app/webroot/ckfinder/userfiles/files/nebalitolinipilegax.pdfIn PDF document text
    • http://www.esthemed.ch/wp-content/plugins/formcraft/file-upload/server/content/files/160a0f81a40cb2---11912557795.pdfIn PDF document text
    • https://art4you.sk/editor_uploads/system/files/negividiriseniku.pdfIn PDF document text
    • http://utopiasacramento.org/clients/0/07/071cdeedc048305be324eb10ab8031d4/File/zirekamizafuzulosaf.pdfIn PDF document text
    • https://drmarlenebothma.co.za/wp-content/plugins/formcraft/file-upload/server/content/files/160986835e6950---30032229370.pdfIn PDF document text
    • https://afriqueitnews.com/wp-content/plugins/super-forms/uploads/php/files/8c61d596ad0d2c2595381cf941301556/77618612514.pdfIn PDF document text
    • http://bochosushi.com/wp-content/plugins/formcraft/file-upload/server/content/files/160986ebf64a9c---bopimiv.pdfIn PDF document text
    • http://xn--80aantfcaehjbxzf1m.xn--p1ai/userfiles/file/lelokofokid.pdfIn PDF document text
    • https://www.sharpeningfactory.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609b7b0e70bd1---65996728362.pdfIn PDF document text
    • https://mindspacepsytherapy.com/upload/ckfinder_temp/files/20210528150610.pdfIn PDF document text
    • http://traditionsradio.com/wp-content/plugins/super-forms/uploads/php/files/7tr9lc2sv1bk0igaqre9g6jsd4/kenumemaf.pdfIn PDF document text
    • https://amiablediamonds.com/wp-content/plugins/super-forms/uploads/php/files/e38c838458ffbc6999241c6cd52a2a68/nanusulawedurokusukidezej.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/FevRqgeaUVY/uplcv?utm_term=from+what+source+do+cells+get+their+foodPDF 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_off0000b29f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB29F 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000cab1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCAB1 14364 bytes
SHA-256: 37cf62edd138de84b8643576f63858823ad46c44b9f673725e82b660d873c395
font_02_sfnt_off0000ee53.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEE53 10980 bytes
SHA-256: 5b9b76d69be5ba4f58c410de920f2942cdc6bd0767249df399cd13f15aa45922