Malicious PDF — malware analysis report

Static analysis result for SHA-256 8907a4b803ec43a1…

MALICIOUS

PDF

159.0 KB Created: 2021-07-28 09:43:47 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: d5e46e430cc2330d44bc34cc2b61beb7 SHA-1: a9e6bb20b92bf6d67bcccd130011513e0600accd SHA-256: 8907a4b803ec43a1175fe13ac869e24e8d7aa986603f9b8648f6afafd314791c
196 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF contains numerous links pointing to compromised WordPress sites, which in turn host other PDF files. This pattern suggests a link farm designed to obscure the ultimate destination, likely a phishing lure or malware download. The ClamAV detection and ML classifier strongly indicate malicious intent, with the primary attack vector being the distribution of malicious content via these linked PDFs.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9983

Heuristics 7

  • 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 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://dorrstrechy.cz/UserFiles/File/8664300426.pdf In PDF document text
    • http://reszke.pl/fckeditor/editor/filemanager/connectors/php/file/wafusalumufuta.pdfIn PDF document text
    • http://hellnocancershow.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b280ce06ad6---makidizaluxiwubapudezimul.pdfIn PDF document text
    • http://www.sempresaude.net/wp-content/plugins/formcraft/file-upload/server/content/files/160cb87192fa32---xigetulugowosugilenewite.pdfIn PDF document text
    • https://cowichanseniors.ca/userfiles/file/bojuvisabuminisafuvogaje.pdfIn PDF document text
    • https://www.spreefahrten-berlin.de/wp-content/plugins/super-forms/uploads/php/files/qfktkudq3jfchuc62lobc8pmrt/rudixuz.pdfIn PDF document text
    • http://hillsdalehorseboarding.com/ckfinder/userfiles/files/79132571231.pdfIn PDF document text
    • http://doublehappyvstheinfinitesadness.com/wp-content/plugins/formcraft/file-upload/server/content/files/16087ba0583c49---91875299958.pdfIn PDF document text
    • http://bilagroup.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a5e5491ad15---paluzorijanigigaxanu.pdfIn PDF document text
    • http://es-umzuege-transporte.de/wp-content/plugins/super-forms/uploads/php/files/233ab94fbbd58ff5078747a03bb64fd3/53400291194.pdfIn PDF document text
    • http://www.lightingandhvacexpo.com/wp-content/plugins/super-forms/uploads/php/files/6835cb45d0b13d4bb4ee57b7e252b4fb/zasurimuvosupanikek.pdfIn PDF document text
    • https://whitelightdesign.com/wp-content/plugins/super-forms/uploads/php/files/abd63779d92475ec7b08cd5c6998dc27/zimexivipoguwavisor.pdfIn PDF document text
    • https://motionslam.com/wp-content/plugins/super-forms/uploads/php/files/f408bd093c180367d10d0644ff5b9042/kolazuniwuz.pdfIn PDF document text
    • http://yossy.biz/userfiles/file/lelubiwutebuma.pdfIn PDF document text
    • http://softtox.com/new/userfiles/file/davewe.pdfIn PDF document text
    • https://yingzhaoliuart.com/upload/file/lufegubekesetu.pdfIn PDF document text
    • http://ridendo.cz/files/file/19748191641.pdfIn PDF document text
    • http://associacaoguainumbi.org.br/wp/wp-content/plugins/formcraft/file-upload/server/content/files/160b04cc75b40d---52498825986.pdfIn PDF document text
    • http://www.tsssport.com/wp-content/plugins/formcraft/file-upload/server/content/files/16078ac31d4351---2766301957.pdfIn PDF document text
    • https://sahodayabbsr.com/test/fckeditor/file/56233420901.pdfIn PDF document text
    • http://www.saito-ken.jp/userdata/file/19035036244.pdfIn PDF document text
    • http://alituncer.com/userfiles/file/64164373767.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/GLLx1DTH0VQ/uplcv?utm_term=iglesia+infantil+asambleas+de+dios+en+guatemalaPDF 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_off00020dfb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x20DFB 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0002260d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x2260D 18604 bytes
SHA-256: 02aa3310fcb93b553eaa4b9afeb67bfa547a3041758137cb79d673c6268658d6
font_02_sfnt_off00025531.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x25531 10788 bytes
SHA-256: c2b1c3d14f662fae61742f8bf3ca62d0f7b931e922b48d8c7180eff8b250f349

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