Malicious PDF — malware analysis report

Static analysis result for SHA-256 4cd376a0b7046727…

MALICIOUS

PDF

116.2 KB Created: 2021-08-06 09:29:28 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-13
MD5: df5d241bb9ab735af95449fafb5a65d7 SHA-1: 42f9224c23d501c9ab081209c80525186a80937f SHA-256: 4cd376a0b70467272d335f3880410b8593afb5db01a127c56ea0e9b9c662017a
156 Risk Score

Malware Insights

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

The PDF contains numerous links, many pointing to external PDF files hosted on various domains, some of which appear to be compromised CMS uploads. The ML classifier and ClamAV detection strongly indicate malicious intent, likely related to phishing or distributing further malware. The document body is heavily obfuscated and unreadable, providing no direct textual clues, but the heuristic findings of link farms and compromised upload locations are significant.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9852

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://pickup-ws.com/userfiles/files/budefefunipajeki.pdf In PDF document text
    • http://flomojapan.com/upload/files/bavuturowujupulizuxade.pdfIn PDF document text
    • https://nowackleverkusen.de/wp-content/plugins/formcraft/file-upload/server/content/files/160bd4fa051d25---zozejapodosefafaxitafuso.pdfIn PDF document text
    • http://bertoniamministrazione.it/bertoni/public/file/zimusoxe.pdfIn PDF document text
    • http://tavaszitura.eu/userfiles/files/mamalomixolabenotimam.pdfIn PDF document text
    • http://www.melodypods.com/wp-content/plugins/formcraft/file-upload/server/content/files/160966438d8d71---15264443783.pdfIn PDF document text
    • https://menu2uplus.com/images/file/81173207962.pdfIn PDF document text
    • http://az4group.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160847d3030165---vusukodumufa.pdfIn PDF document text
    • https://triptoboloyfoundation.org/editorsfiles/files/sejigakasanawamuwafa.pdfIn PDF document text
    • http://www.sevenchurchestour.net/seven/wp-content/plugins/formcraft/file-upload/server/content/files/16093a265463d2---67992796363.pdfIn PDF document text
    • http://lyshiying.com/d/files/fopemobur.pdfIn PDF document text
    • http://www.caribbeandentist.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607e9dab5a86d---doronoxevumupoxikibowa.pdfIn PDF document text
    • https://www.histoiresdegroupes.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609c79bc179f4---fininozezosenuzizujuva.pdfIn PDF document text
    • http://arc-en-cielproduce.com/ckfinder/userfiles/files/xukufowajoxu.pdfIn PDF document text
    • https://too.kg/wp-content/plugins/super-forms/uploads/php/files/0899df0a586f21dbdd50daec1672b2e6/wipowuja.pdfIn PDF document text
    • http://sarljarry.fr/userfiles/file/xiwafega.pdfIn PDF document text
    • http://acecaalcoy.com/userfiles/file/62099643257.pdfIn PDF document text
    • https://binhruamuinanobac.com/wp-content/plugins/super-forms/uploads/php/files/gucsu5jfo402fm2f01bm9b1sfa/95423121631.pdfIn PDF document text
    • https://hpx.com.ua/wp-content/plugins/super-forms/uploads/php/files/d474b88cfb750014eccabee40b0aa4d2/41988503998.pdfIn PDF document text
    • https://mymango.ru/wp-content/plugins/super-forms/uploads/php/files/13f1110918c90570e1150f6a4048ee54/nalurupegoru.pdfIn PDF document text
    • http://www.telsercom.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b5e78dcdba8---24295908824.pdfIn PDF document text
    • https://tucsonhomewindowtint.com/wp-content/plugins/super-forms/uploads/php/files/005724df0a6d2cbfc19b0d00854671d3/93780745084.pdfIn PDF document text
    • https://nsck-cykelmotion.dk/ckfinder/userfiles/files/lodabuguzinazidatixedir.pdfIn PDF document text
    • https://nobleanimalsanctuary.org/wp-content/plugins/super-forms/uploads/php/files/tmp/17692898675.pdfIn PDF document text
    • https://impariant-club.ru/wp-content/plugins/super-forms/uploads/php/files/e0c1edf5da4afa423f84e4b689ae2468/xakazopujox.pdfIn PDF document text
    • http://aldo-ins.com/userfiles/file/59612014260.pdfIn PDF document text
    • https://tranduongauto.com/app/webroot/files/images/pages/files/refakuwaxagoja.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/6naE_Nh8_CY/uplcv?utm_term=matematicas+simplificadas+primera+edicion+pdfPDF 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_off0001600a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1600A 10772 bytes
SHA-256: c466d05e6da497d2498237da4d99252d282313b4d63bd0ac0581fe769afcd380
font_01_sfnt_off000178c5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x178C5 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off000190d7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x190D7 18556 bytes
SHA-256: 72b18a9a115645badd9643c55fc33e6700ed6936aabd4707e7cfe3e362b93b7d