Malicious PDF — malware analysis report

Static analysis result for SHA-256 bac4f40c431dfdad…

MALICIOUS

PDF

70.5 KB Created: 2021-09-26 18:14:18 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-23
MD5: 8a2e8a10dc03cecddd654af3ba2459fd SHA-1: f1725d4bc7016ee0d06bc14ebc6c0654079939a7 SHA-256: bac4f40c431dfdadd82e3f1a113b3522b59a0851c79d98fb21eef5420fa93b15
156 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs, many of which point to compromised CMS upload directories, suggesting an attempt to host malicious content or redirect users to phishing sites. The ML classifier and ClamAV detection strongly indicate malicious intent, likely related to phishing or malware delivery via a link farm. No scripts were extracted, and the document body was unreadable, so the attack pattern is inferred from the URL analysis and heuristic firings.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9982

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://sukienmiennam.com/userupload/files/22584309160.pdf In PDF document text
    • http://www.gradur.ba/wp-content/plugins/formcraft/file-upload/server/content/files/161389ce4b1705---tatozosome.pdfIn PDF document text
    • http://vinhthuan.com/upload/files/88225684027.pdfIn PDF document text
    • https://csmgh.net/pevron/www/img/file/vixomodesimoduduk.pdfIn PDF document text
    • http://argra.rs/wp-content/plugins/formcraft/file-upload/server/content/files/161423d037b5a7---80919396447.pdfIn PDF document text
    • https://totspotdaynursery.co.uk/ckfinder/userfiles/files/limodiwowopuwavaxe.pdfIn PDF document text
    • http://www.chinahkcarplate.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614e66e3e5fcf---bawos.pdfIn PDF document text
    • http://www.radio-kum.si/data/files/tuwolarovifaxugepewun.pdfIn PDF document text
    • http://www.pes.edu.mn/ckfinder/userfiles/files/bokunefijawet.pdfIn PDF document text
    • https://benhgout.net/uploads/Files/file/14583076914.pdfIn PDF document text
    • http://villalapinetafavignana.it/userfiles/files/bamujizonumi.pdfIn PDF document text
    • https://szaniterplaza.hu/ckfinder/userfiles/files/padikevokutigopidixodofas.pdfIn PDF document text
    • http://binhchuachay.info/Images_upload/files/gamilafoxofi.pdfIn PDF document text
    • http://paraleumarian.ro/app/webroot/files/userfiles/files/lixonanogadidesamatero.pdfIn PDF document text
    • https://emergent-partners.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613147fa510a1---1114071473.pdfIn PDF document text
    • http://amongelite.com/ci/userfiles/files/gumoxi.pdfIn PDF document text
    • http://www.nbrownies.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1614ae2f9beaa3---33440776819.pdfIn PDF document text
    • https://www.alongsideasia.com/wp-content/plugins/super-forms/uploads/php/files/c6ae15c02a10c487a406c1afa46d48cf/xelarudabozix.pdfIn PDF document text
    • https://hbphoto.ca/resimler/files/46188477292.pdfIn PDF document text
    • https://pierrelemagicien.com/userfiles/file/11162959943.pdfIn PDF document text
    • http://musicandyouapp.com/webupload/editorimg/files/8156079910.pdfIn PDF document text
    • https://duel.pl/userfiles/file/batiletenodewologivagaz.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/ngfLrbzwjls/uplcv?utm_term=plato+trial+and+death+of+socrates+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_off0000b251.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB251 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000ca68.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCA68 10716 bytes
SHA-256: 52a54dda3d2ee8479299f6528c8f80e4dd5b56a06ecdfb63307345cadce0359a
font_02_sfnt_off0000e2ef.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE2EF 16088 bytes
SHA-256: d77e8225b05eafcefd11bcbcdbd6fdd213e88d7e452cf72d735817d13fe1b654