Malicious PDF — malware analysis report

Static analysis result for SHA-256 866543ec9eafb983…

MALICIOUS

PDF

72.0 KB Created: 2021-10-08 19:45:25 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-24
MD5: ff384899dd49bdcd9a07fca69ce5d7b7 SHA-1: b4e1f2840d3a395695617f373fdf46444b322e1d SHA-256: 866543ec9eafb9839ec93e4ab9bc1e1f363897ceb20f2e3460598e4b0f96b38a
156 Risk Score

Malware Insights

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

The sample is identified as malicious by ClamAV and an ML classifier, and exhibits characteristics of a link farm. Multiple heuristics indicate the PDF contains numerous external URIs, some pointing to compromised WordPress upload directories, suggesting an attempt to lure users to malicious sites. The document body is heavily obfuscated and unreadable, providing no direct content clues, but the overall structure and URL findings strongly suggest a phishing or malware distribution vector.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

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://drafthe.ru/uplcv?utm_term=simplifying+expressions+worksheet+year+7 PDF link annotation
    • https://ag-concept.ru/wp-content/plugins/super-forms/uploads/php/files/5eaeef54814d581e69fe9da5d3286185/morazojut.pdfIn PDF document text
    • http://agriturismocorteerbatici.it/userfiles/files/mubidepajujewolewewa.pdfIn PDF document text
    • http://schroniskoorzechowce.pl/ckfinder/userfiles/files/bevasaluxupegakebob.pdfIn PDF document text
    • https://ijfbacknumber.com/editor_up/33096665905.pdfIn PDF document text
    • https://ratodua.com/contents/files/mafubenowodixotivukowu.pdfIn PDF document text
    • http://recamonde.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/16147d9cdaca8a---73564005065.pdfIn PDF document text
    • http://thuocnam.xyz/images/files/29415940954.pdfIn PDF document text
    • https://microfocus-realize2020mea.com/wp-content/plugins/super-forms/uploads/php/files/7405dbc0726207e40b677dd5a835b2c9/85105979710.pdfIn PDF document text
    • https://manhremhoangvan.vn/wp-content/uploads/files/86143918162.pdfIn PDF document text
    • https://unitytradecapital.com/ckfinder/userfiles/files/19287933870.pdfIn PDF document text
    • http://lamachine.nl/userfiles/file/59559961342.pdfIn PDF document text
    • https://klubkanine.com/home/klub/public_html/ckfinder/userfiles/files/tinusetovuxajozi.pdfIn PDF document text
    • http://kbcsisa.com/upload/fckeditor/file/92207498541.pdfIn PDF document text
    • http://banglenhospital.com/UserFiles/File/40260084435.pdfIn PDF document text
    • http://kuppersbusch.hu/userfiles/files/kujipaziru.pdfIn PDF document text
    • http://change4best.ru/upload/file/vabosukafuximede.pdfIn PDF document text
    • https://democv.associasuite.com/imagenes/contenidos/files/26256308480.pdfIn PDF document text
    • https://stmpallet.com/ckfinder/userfiles/files/kapivobojosusolar.pdfIn PDF document text
    • https://nikunjfoundation.org/ckfinder/userfiles/files/puwiwuneg.pdfIn PDF document text
    • http://namuvaldymas.lt/userfiles/file/vumewarala.pdfIn PDF document text
    • http://cungcapbaoduongcuanhatban.com/upload/files/71200459145.pdfIn PDF document text
    • http://fgsconsulta.com.br/ckfinder/uploads/userfiles/files/gunolorabivatoxarozazifo.pdfIn PDF document text
    • http://www.videobezopasnost.ru/ckfinder/userfiles/files/93570566466.pdfIn PDF document text
    • https://purpleleafestatebuyers.com/wp-content/plugins/formcraft/file-upload/server/content/files/1615a89b583fa9---72661757410.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_off0000b683.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB683 16036 bytes
SHA-256: 3b15ede9a353437d04f59ca4ab3dec2a865cea45a7d158f6088dceeccd068acd
font_01_sfnt_off0000df28.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDF28 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000f73f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF73F 11324 bytes
SHA-256: 2872044a7be2e5cb391f0308571e6cef671ed18fc9de721d26bf956494737dbf