Malicious PDF — malware analysis report

Static analysis result for SHA-256 800fb56fc4845389…

MALICIOUS

PDF

71.0 KB Created: 2021-09-01 21:43:45 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: cd44d1e0d684967d5d32277df936b00a SHA-1: 4f567034db8e5ffb104c443c8bebfd387fa70cab SHA-256: 800fb56fc48453891b6e6a6e29487146d638163810f7ca336212124e298d356e
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.001 User Execution: Malicious Link

The PDF file was detected as malicious by ClamAV and an ML classifier. It contains numerous embedded URLs, many of which point to disposable hosting or compromised CMS upload directories, indicating a link farm designed to redirect users. The heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' specifically flags this pattern. The document body is unreadable, but the presence of these links strongly suggests a phishing or malware distribution attempt.

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 http://pomodorolennep.de/gfx/userfiles/files/50296700964.pdf In PDF document text
    • https://juhaszautovill.hu/userfiles/file/18954093542.pdfIn PDF document text
    • http://sarljarry.fr/userfiles/file/wotasunu.pdfIn PDF document text
    • http://www.ecvbrass.ch/user/web/file/38175761423.pdfIn PDF document text
    • http://bike-aholic.com/UserFiles/file/9675144816.pdfIn PDF document text
    • https://norservis.info/files/files/6151293361.pdfIn PDF document text
    • https://xn--22ck6bdp5cach0mc23a.com/ckfinder/userfiles/files/25132857905.pdfIn PDF document text
    • https://bk.knu.ac.kr/ckfinder/userfiles/files/57121090187.pdfIn PDF document text
    • http://kientrucphatloc.com/upload/files/24414660598.pdfIn PDF document text
    • http://artpolyclinic.com/file/files/rilafetawopof.pdfIn PDF document text
    • http://saharun.org/uploads/ckfinder/userfiles/files/92611114035.pdfIn PDF document text
    • https://www.chortho.co.uk/wp-content/plugins/super-forms/uploads/php/files/hp1hbkimb33jqqistphn9ep0v0/75322114580.pdfIn PDF document text
    • http://vivaldiskibus.com/FileData/ckfinder/files/20210713_FDB36C75934091B4.pdfIn PDF document text
    • https://www.fecomerciomg.org.br/wp-content/plugins/formcraft/file-upload/server/content/files/1606cd6ffc7c83---26909669817.pdfIn PDF document text
    • http://bjhtdszdh.com/v15/Upload/file/202183195044740.pdfIn PDF document text
    • http://polyalpan.hu/_user/file/gixagosurukisibe.pdfIn PDF document text
    • https://learningsolution.ca/userfiles/files/56020551337.pdfIn PDF document text
    • https://dildendilecevirievi.com/upload/ckfinder/files/lunogu.pdfIn PDF document text
    • http://www.nisbd.com/wp-content/plugins/formcraft/file-upload/server/content/files/160aa8dc511056---21565613223.pdfIn PDF document text
    • https://jobtiara.com/files/files/6373570988.pdfIn PDF document text
    • http://chieucoingason.vn/files/torodetulale.pdfIn PDF document text
    • http://chieucoingason.vn/files/28535746011.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/ngfLrbzwjls/uplcv?utm_term=converting+document+to+pdf+formatPDF 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_off0000b5b7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB5B7 15444 bytes
SHA-256: 421f7ca9f7f4c6afb5e48f12671779db959d6438a2acfe4b49d848320349ced5
font_01_sfnt_off0000dd22.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDD22 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000f539.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF539 10948 bytes
SHA-256: ee02f0e05318720fb8653305d6b9ef0e995a40f6efeb4fa0ae3c3c92301f17fb