Malicious PDF — malware analysis report

Static analysis result for SHA-256 5428d18a0dd5c32f…

MALICIOUS

PDF

94.1 KB Created: 2021-09-08 21:05:35 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: 327a57104d1f48420d63d84d522ec43e SHA-1: 9d2c9a2f4dac7ab8938d450dc0c0897216481bc3 SHA-256: 5428d18a0dd5c32faeb388c7fba7b13537031dd779070a694ef0a212c635988a
156 Risk Score

Malware Insights

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

The PDF file was identified as malicious by ML classifiers and ClamAV, specifically as a phishing trojan. It functions as a link farm, distributing malicious PDFs via compromised WordPress sites and disposable hosting. The embedded URLs point to various PDF files hosted on these compromised or disposable domains, indicating a distribution mechanism for further malicious payloads.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9965

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://cuboni.com/uploadfile/hong202109041553207978.pdf In PDF document text
    • http://tecs4.com/intranet/ckfinder/userfiles/files/41046010322.pdfIn PDF document text
    • https://yaslibakicisi.net/userfiles/file/piledejumixokuxaxerag.pdfIn PDF document text
    • https://www.pepinieres-gey.fr/ckfinder/userfiles/files/zujipe.pdfIn PDF document text
    • https://sirikulsteel.com/wp-content/plugins/formcraft/file-upload/server/content/files/16137c78ab7a80---tosefipijuki.pdfIn PDF document text
    • http://www.cascinasorigherio.it/wp-content/plugins/formcraft/file-upload/server/content/files/161376d6a5ccfc---gurexupabavuviviwetetoka.pdfIn PDF document text
    • http://tupnate.com/ckfinder/userfiles/files/wefawimixezozejukuge.pdfIn PDF document text
    • http://szcftz.com/upload/tokugenusonijusigadefena.pdfIn PDF document text
    • http://ammk.sk/userfiles/file/6830013758.pdfIn PDF document text
    • http://bobhendrix-law.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/1807964047.pdfIn PDF document text
    • http://uitetenindex.nl/images/uploads/93652704691.pdfIn PDF document text
    • https://vvpta-irvine.org/userfiles/file/zagedokodi.pdfIn PDF document text
    • http://metzlerranch.com/userimages/81464829731.pdfIn PDF document text
    • http://vejwun.cz/images/72119315260.pdfIn PDF document text
    • http://mizuho-co.net/file/ck/files/54520365839.pdfIn PDF document text
    • http://www.expertnutritionadvisor.com/wp-content/plugins/formcraft/file-upload/server/content/files/16132214e9b5f5---bufemi.pdfIn PDF document text
    • http://audiomaster.se/wp-content/plugins/formcraft/file-upload/server/content/files/1613775f772eda---bavedujin.pdfIn PDF document text
    • http://omonetach.pl/foto/ilustracje/file/lorugofitizebaj.pdfIn PDF document text
    • https://stephan-kratt.de/data/reiterhof/userfiles/file/22227970237.pdfIn PDF document text
    • http://unitec-egypt.net/userfiles/file/57110312726.pdfIn PDF document text
    • http://support-cmu.com/filedata/file/damunorevokuw.pdfIn PDF document text
    • http://fst-uinsu.net/userfiles/files/44629593583.pdfIn PDF document text
    • http://www.likoda.com.tw/upload/ckimg/files/nonenosefefep.pdfIn PDF document text
    • http://topenglish.sk/app/webroot/gallery/files/gapabofujifedo.pdfIn PDF document text
    • http://ciccioinpentola.com/userfiles/files/zamumumajaf.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/A3Ryygt5BCM/uplcv?utm_term=flexographic+printing+machine+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_off000108f5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x108F5 10976 bytes
SHA-256: f4cabaaceee461ac1cb46ec1ebff0cafdf4c340e8f6e1f6abb5499681ef2da22
font_01_sfnt_off00012208.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12208 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00013a1a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13A1A 18632 bytes
SHA-256: 8a775af2b08fdc98220f430e9684b0398ce6700688e444f5d6060068275b3c6f

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