Malicious PDF — malware analysis report

Static analysis result for SHA-256 a5c5f6d46a7d9d56…

MALICIOUS

PDF

78.9 KB Created: 2021-09-05 16:46:22 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-07
MD5: aed58787c8aa4484fdeaf8d6ce395d55 SHA-1: 3b1000c609e834e1756bd89042324687f978b5e0 SHA-256: a5c5f6d46a7d9d5692b0119d59bffaa4dc1e0fc54da5babf4d04d1cbe70929a6
156 Risk Score

Malware Insights

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

The PDF file was identified as malicious by ML classifiers and ClamAV, indicating a phishing or trojan threat. It functions as a link farm, containing numerous URLs that point to external resources, some of which are hosted on compromised WordPress sites. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, suggesting it's not intended for direct user reading but rather for programmatic interaction.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9985

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://pcparts.fr/ckfinder/userfiles/files/40962540968.pdf In PDF document text
    • http://legalinet.eu/userfiles/files/wukuvenewivesuvifibovu.pdfIn PDF document text
    • http://patronusalapitvany.hu/public_html/upload/58250832014.pdfIn PDF document text
    • http://tomaszskiba.com/userfiles/file/31976204658.pdfIn PDF document text
    • https://lerong.vn/wp-content/plugins/super-forms/uploads/php/files/32609df67d16d975b985e866dd78bd31/83044447220.pdfIn PDF document text
    • http://capitolmetrophysicaltherapy.com/files/files/wumidixewajasojufapatu.pdfIn PDF document text
    • https://universal4shipping.net/userfiles/file/gudaganorab.pdfIn PDF document text
    • http://color-gateway.com/userfiles/file/posuput.pdfIn PDF document text
    • http://elsekmont.eu/userfiles/file/67394511962.pdfIn PDF document text
    • https://lodoshosting.com/calisma2/files/uploads/talotazitipiv.pdfIn PDF document text
    • http://bearings-home.com/userfiles/file/rutazemulamaka.pdfIn PDF document text
    • https://tortugafilms.ca/adminfiles/file/85388491896.pdfIn PDF document text
    • https://bititechnika.com/uploads/file/vuvezexeratikupufasag.pdfIn PDF document text
    • https://jamurgoreng.net/contents//files/sesotasosujiva.pdfIn PDF document text
    • https://www.parkgest.ch/wp-content/plugins/formcraft/file-upload/server/content/files/160b8118600d44---71757093254.pdfIn PDF document text
    • http://rudolphi.nu/userfiles/file/83468764490.pdfIn PDF document text
    • https://pensionatiitalianiinportogallo.it/wp-content/plugins/super-forms/uploads/php/files/ce5939a7412a19eded62e82e49d7e6f8/lixufudu.pdfIn PDF document text
    • http://imailbox.nl/images/uploadedimages/file/53299635311.pdfIn PDF document text
    • https://avela.md/userfiles/file/92543834859.pdfIn PDF document text
    • https://bokseinstituttet.dk/wp-content/plugins/formcraft/file-upload/server/content/files/160adc067657fd---gipifarozexapuganor.pdfIn PDF document text
    • http://studiotecnicopetrillo.eu/userfiles/files/zusibuzofiwubakes.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/6naE_Nh8_CY/uplcv?utm_term=ordering+rational+numbers+worksheet+with+answersPDF 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_off0000cceb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCCEB 11140 bytes
SHA-256: e8a3fc531fa3da42ca943521a8c0bf6ae966c9dcf68fbccfc899c476ee147532
font_01_sfnt_off0000e694.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE694 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000fea6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFEA6 17420 bytes
SHA-256: 43a575d0e261b160ae591b04157444a013d8ecc75c10cb4048b11736025ebacd