Malicious PDF — malware analysis report

Static analysis result for SHA-256 83d3c91eff77685b…

MALICIOUS

PDF

75.9 KB Created: 2021-09-19 06:01:16 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: 850f9246f8144834f6a7de528f169cbf SHA-1: 89d645fb82970b62687040a896a96a577ddec650 SHA-256: 83d3c91eff77685b73137eba4579dbf43eb3ff4cf62c999a909ef20557c47d8f
156 Risk Score

Malware Insights

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

The file is a PDF that contains a large number of embedded URLs, many of which point to compromised websites or disposable hosting. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for phishing or redirecting users to malicious content. The PDF_SEO_DISPOSABLE_LINK_FARM heuristic confirms the nature of the links as a link farm.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9947

Heuristics 6

  • 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 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://camberwelltaxi.com/survey/userfiles/files/89638765383.pdf In PDF document text
    • https://yenhuy.vn/upload/files/lasodoridazinakemobupod.pdfIn PDF document text
    • https://sakesushimn.com/userfiles/files/62684350468.pdfIn PDF document text
    • https://partnermind.cz/images/files/rexitajogulumus.pdfIn PDF document text
    • http://casier-a-bouteilles.com/file/78693127387.pdfIn PDF document text
    • https://mkontakt.pl/dat/file/punumajovakolimivaveg.pdfIn PDF document text
    • https://www.tonygssoulfood.com/wp-content/plugins/super-forms/uploads/php/files/229b997913dbbacd1106f61f50a6174e/49986798132.pdfIn PDF document text
    • http://scea.edu.mn/ckfinder/userfiles/files/12580078588.pdfIn PDF document text
    • https://uudanbury.life/files/file/baxisunam.pdfIn PDF document text
    • https://brusroom.com/wp-content/plugins/super-forms/uploads/php/files/562514587225dffe3d79520c26ee2927/pefadipowa.pdfIn PDF document text
    • http://www.absolutecateringla.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613415f9c8066---59989241641.pdfIn PDF document text
    • http://marathon-gexin.com/Uploadfiles/files/7731993019.pdfIn PDF document text
    • https://egokituz.eus/files/galeria/files/47183110683.pdfIn PDF document text
    • http://www.sunarozlem.com.tr/wp-content/plugins/super-forms/uploads/php/files/lq2dd5fe0bilgbn83585qcgle7/86772183341.pdfIn PDF document text
    • http://iamsoldierfit.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613717dc6fdf9---64020692241.pdfIn PDF document text
    • https://euinsuti.uniluxgym.ro/app/webroot/files/userfiles/files/52019437788.pdfIn PDF document text
    • https://spirit-legend-enterprises.com/webroot/editor-uploads/files/sumitig.pdfIn PDF document text
    • https://marblo.com/app/webroot/img/files/wavexudikoxaz.pdfIn PDF document text
    • https://kvgrup.com.ua/wp-content/plugins/formcraft/file-upload/server/content/files/161469d0f6b30c---7394013787.pdfIn PDF document text
    • http://kulturazebrak.cz/userfiles/nujirisukeb.pdfIn PDF document text
    • http://security-m.jp/tool/images/file/52352608600.pdfIn PDF document text
    • https://dbhattacharjee.com/ckfinder/userfiles/files/19568527765.pdfIn PDF document text
    • https://sunnyvale.com/wysiwygfiles/file/ziniwetugosusapumak.pdfIn PDF document text
    • https://abisspaandboutique.com/nbloom/fckuploads/file/69970716411.pdfIn PDF document text
    • http://gonvvama.net/filespath/files/20210916234245.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/ngfLrbzwjls/uplcv?utm_term=watch+the+croods+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_off0000c31d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC31D 10324 bytes
SHA-256: d01b89047357c1a4e518c2f182f34583bf85347884e74bb420002c32cd79af92
font_01_sfnt_off0000da97.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDA97 18284 bytes
SHA-256: e28a5307cbed756d7219fe36601439cb01d1cae4c80456100a8354d23749782f
font_02_sfnt_off00010a5f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10A5F 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1