Malicious PDF — malware analysis report

Static analysis result for SHA-256 5f23aa51ac0d7251…

MALICIOUS

PDF

98.8 KB Created: 2021-07-26 06:11:23 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-14
MD5: 4b9da13ebf3eacf95ca73de0ab3087f4 SHA-1: 1e4cbc7d82b57537c5f8ae608bf17223c2ffb939 SHA-256: 5f23aa51ac0d7251b87588585c51fee22cfab3e8069c9d80f04cb3049ef897ba
156 Risk Score

Malware Insights

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

The sample is a PDF file detected by ClamAV as a phishing trojan. Static analysis reveals it functions as a link farm, containing numerous URLs pointing to various domains, some of which are hosted on compromised CMS upload storage. The ML classifier also strongly indicated maliciousness. The primary purpose appears to be directing users to external resources, likely for phishing or further malware delivery.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9942

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://a-kamen.com/userfiles/file/60962577449.pdf In PDF document text
    • http://hanasushi6.com/uploads/files/genexuwaropofasufodelukav.pdfIn PDF document text
    • https://ehotelgateway.com/bot/ckfinder/uf/files/jarevusetagavufofis.pdfIn PDF document text
    • https://alcc.vn/wp-content/plugins/super-forms/uploads/php/files/0b34dukr4it40k5v83cgth4bem/13180170664.pdfIn PDF document text
    • http://fine-trading-knotwork.de/uploads/media/gabakiz.pdfIn PDF document text
    • http://dilimkebab.com/userfiles/file/91140625128.pdfIn PDF document text
    • https://alignerco.com/wp-content/plugins/super-forms/uploads/php/files/695fc5a6f7289775011d15049d2951c0/10424687540.pdfIn PDF document text
    • http://apnorajasthan.net/userfiles/file/bijimupixizuninefowuwu.pdfIn PDF document text
    • http://ekopaczka.pl/imgbrama/files/57063765074.pdfIn PDF document text
    • https://anukulagrotech.com/userfiles/file/mixodoneregekolegujezabas.pdfIn PDF document text
    • https://htfcompact.com/wp-content/plugins/super-forms/uploads/php/files/3bdad2336f705208174bfde36fdc7aa2/lozesowa.pdfIn PDF document text
    • http://makaeximworld.com/wp-content/plugins/formcraft/file-upload/server/content/files/16085643d7f747---64546400147.pdfIn PDF document text
    • http://www.mvdisposal.com/wp-content/plugins/formcraft/file-upload/server/content/files/160abb8b7d9aef---gepedimetevulev.pdfIn PDF document text
    • https://www.andeanskyline.com/wp-content/plugins/formcraft/file-upload/server/content/files/160be24a3adcaa---mipobividulenozekije.pdfIn PDF document text
    • https://www.properties-thassos.com/wp-content/plugins/super-forms/uploads/php/files/4h3pbbdthkol1f8931dno9tag4/99010823198.pdfIn PDF document text
    • https://www.carlosfunes.es/wp-content/plugins/formcraft/file-upload/server/content/files/16076b21a3b850---18245408096.pdfIn PDF document text
    • http://ankurgroups.com/userfiles/file/15803567668.pdfIn PDF document text
    • https://cubic.is/userfiles/file/90536819025.pdfIn PDF document text
    • http://oneself.pro/wp-content/plugins/formcraft/file-upload/server/content/files/160b8ada52b262---73780284659.pdfIn PDF document text
    • http://anhuicrew.com/upload_fck/file/2021-7-6/20210706053641486231.pdfIn PDF document text
    • https://sgpropertylawyers.com/wp-content/plugins/super-forms/uploads/php/files/f8929e0dfee5dc1f5db849a8ab58214f/69225207710.pdfIn PDF document text
    • http://debden.org/userfiles/file/nagetek.pdfIn PDF document text
    • https://detector-billetes.com/Imagenes/file/3929172579.pdfIn PDF document text
    • https://alphaveneers.co.uk/wp-content/plugins/super-forms/uploads/php/files/a919a838818548c550b960af27eb7559/81252209763.pdfIn PDF document text
    • https://alsterparkett.de/wp-content/plugins/super-forms/uploads/php/files/2bn1ieokjn87r5uj5ueca3kf5e/ludozas.pdfIn PDF document text
    • http://rogo-rotterdam.nl/files/73951076263.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/fzgW7-mxBc0/uplcv?utm_term=aesculap+general+catalog+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_off00011f6c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11F6C 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off00013783.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13783 10784 bytes
SHA-256: 999b44cc49aee534216679e97d66cf8e809efdd5ebdc4dfb69a5e65b1da3fe25
font_02_sfnt_off0001505b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1505B 17004 bytes
SHA-256: 7ce19ede2eab8859d69dfa02cdcd8aee4c3a8dc9a6e95b2e1ef1383b9fb22063