Malicious PDF — malware analysis report

Static analysis result for SHA-256 b5d5194c873174c2…

MALICIOUS

PDF

80.7 KB Created: 2021-09-03 03:27:57 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: a50b55161ec1b3547d6112aeedc18509 SHA-1: f944b161998adbde468dd8563e8623c61010a974 SHA-256: b5d5194c873174c2da1c80004cd1ec7cab95a4341aede5967a0c548cccd5de51
156 Risk Score

Malware Insights

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

The sample was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. Heuristics identified it as a link farm, with multiple URLs pointing to compromised WordPress sites and disposable hosting. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, suggesting it's not intended for human readability but rather to host these links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

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://landlorddebtadvisory.com/wp-content/plugins/super-forms/uploads/php/files/4shbbmdmttpv1ct3j81ghriuo0/77632388276.pdf In PDF document text
    • http://geoplan.su/userfiles/file/wemuvu.pdfIn PDF document text
    • https://carthink.org/wp-content/plugins/formcraft/file-upload/server/content/files/16095d84def828---13771843765.pdfIn PDF document text
    • https://poolpoint.be/uploads/file/vasabeti.pdfIn PDF document text
    • https://mindweave.co.uk/wp-content/plugins/super-forms/uploads/php/files/ajfbdveor2284j76vko71rqiid/58761782978.pdfIn PDF document text
    • http://aire-limpio.com/img/editor/file/nizatosajonenerenokosedo.pdfIn PDF document text
    • http://jeugdopdewetenschapsagenda.nl/wp-content/plugins/formcraft/file-upload/server/content/files/160c8a2b496ed9---nopomemofuvikaw.pdfIn PDF document text
    • http://abapaposentados.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1608a6df89e77b---38729838713.pdfIn PDF document text
    • https://brianhigbielaw.com/UserFiles/file/60700222685.pdfIn PDF document text
    • http://xn--m1age8bh.xn--p1ai/files/file/9177519285.pdfIn PDF document text
    • https://mandalaconfeccao.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160bfd967ab739---94378637337.pdfIn PDF document text
    • https://ryokanclub.com/FileData/ckfinder/files/20210725_AF1413D55998250F.pdfIn PDF document text
    • http://www.consorcio.edu.pe/wp-content/plugins/formcraft/file-upload/server/content/files/1611e442a68fb4---beginewago.pdfIn PDF document text
    • https://www.infratechgroep.nl/wp-content/plugins/super-forms/uploads/php/files/95b511cfab87230d8698ced5e913977d/24752808616.pdfIn PDF document text
    • https://condicionamentofisico.com/arquivos/file/54153709033.pdfIn PDF document text
    • http://gpe-el.pro/ckfinder/userfiles/files/wivipogunujetubowilu.pdfIn PDF document text
    • http://brodart01.com/wp-content/plugins/super-forms/uploads/php/files/op56puoh73e9a55d8dunfmbhpv/nutimukanarazizefuxodufav.pdfIn PDF document text
    • https://www.cdscabling.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/1607e49e42286f---49720285494.pdfIn PDF document text
    • http://netpost.vn/upload/userfiles/files/nobexafopurexef.pdfIn PDF document text
    • http://www.scmphotography.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/160b58a8b1f409---13623838710.pdfIn PDF document text
    • http://mail.teleserviciomalaga.com/ckfinder/userfiles/files/70811246528.pdfIn PDF document text
    • https://hotelritariccione.it/wp-content/plugins/formcraft/file-upload/server/content/files/160786805c302e---64663129628.pdfIn PDF document text
    • http://kdwatch.net/upload/files/2021070808441796.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/1KS0DP0cxss/uplcv?utm_term=fraction+exercises+for+grade+3+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_off0000d40e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD40E 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000ec20.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEC20 17500 bytes
SHA-256: 26a5fbaa354cdb934bd4b161ce61a853738285dac80f8633c2b638fb024ffc93
font_02_sfnt_off00011989.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11989 11000 bytes
SHA-256: 378a52872deef733bc52191d964c04cbb228f3ff3c82f0b5cce0249747f12432

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