Malicious PDF — malware analysis report

Static analysis result for SHA-256 27af5a2e182887e3…

MALICIOUS

PDF

80.7 KB Created: 2021-09-12 17:33:19 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: 8f2275c5ec9b90dad9a7d856d461cc1a SHA-1: 44008d3604e6fc17f53714f325eb3dde5b5883b4 SHA-256: 27af5a2e182887e3ce254c31a970bcfa25a0f103f57043f5399bc240de39f50f
176 Risk Score

Malware Insights

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

The PDF was flagged by ClamAV as 'Pdf.Phishing.Trojan' and ML classifiers indicated a high probability of maliciousness. Heuristics identified it as a link farm on disposable hosting, with multiple URLs pointing to compromised CMS uploads and potentially malicious content. The document body, though heavily obfuscated, contains references to wkhtmltopdf, suggesting it was generated programmatically to host these links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

Heuristics 7

  • 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.
  • QR-code redirect lure medium SE_QR_LURE
    Document instructs the user to scan a QR code with a phone — consistent with QR phishing, but also common in legitimate documents
  • 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://wx-test.com/upload/ckimg/files/202109121917383969.pdf In PDF document text
    • http://www.pattyn360.com/upload/forum/files/94225768024.pdfIn PDF document text
    • http://whipitleather.com/userfiles/file/kezizetujekasewewa.pdfIn PDF document text
    • https://hoanghaie.com/Images_upload/files/kasasuzarewapisebiwumiri.pdfIn PDF document text
    • http://serramentisiciliano.it/userfiles/files/sobafagudavezuniw.pdfIn PDF document text
    • http://tubemakingmachine.com/uploadfile/files/66448912070.pdfIn PDF document text
    • https://zlatartopalovic.rs/files/31551981317.pdfIn PDF document text
    • http://pytextiles.com/userfiles/file/17714693429.pdfIn PDF document text
    • https://www.pactforfamilies.org/ckfinder/userfiles/files/64528268772.pdfIn PDF document text
    • http://champagne-marc-chauvet.com/images/files/96314122936.pdfIn PDF document text
    • https://www.birdandwildlifeteam.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613a2e884c46b---99436386564.pdfIn PDF document text
    • https://veritiesinstitute.com/wp-content/plugins/super-forms/uploads/php/files/bd728174fb8da632fbf7559c8467abb3/lakofutukobona.pdfIn PDF document text
    • https://archielectronics.com/userfiles/files/15799501852.pdfIn PDF document text
    • https://plantbiochem.com/ckfinder/userfiles/files/44666867844.pdfIn PDF document text
    • https://fzclicks.com/demo/files/editor/file/7300684276.pdfIn PDF document text
    • https://pepsima.biz/files/file/vipojeroverozopujinapono.pdfIn PDF document text
    • http://bilcafe.it/userfiles/file/badojirovubererira.pdfIn PDF document text
    • http://instant-image.net/UserFiles/Site/File/wonowifoli.pdfIn PDF document text
    • http://2018.letnifestiwal.pl/ckfinder/userfiles/files/46643533600.pdfIn PDF document text
    • http://tuhocxuatnhapkhau.com/uploads/ckfinder/files/24733633534.pdfIn PDF document text
    • https://40parables.com/wp-content/plugins/super-forms/uploads/php/files/96aede257f5abf761328d1fe73d28d90/podazebowigusinefitipez.pdfIn PDF document text
    • http://runnersavezzano.it/public/userfiles/file/67636002171.pdfIn PDF document text
    • https://paardenwelzijnscheck.nl/app/webroot/files/ckeditor_files/files/jawanokufukuxikum.pdfIn PDF document text
    • https://brs.jo/userfiles/files/67539409138.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/3CAf4wW3hvY/uplcv?utm_term=android+car+apkPDF 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_off0000d8c1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD8C1 17824 bytes
SHA-256: c93058077534ca52b800890ac7926d7126728b7c3a691b76ffc10391c6596064
font_01_sfnt_off000106ae.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x106AE 10136 bytes
SHA-256: 728cf8591ed9987a987f5f842e0e4fcc45982ed3a223b66c24937bcdd8d5c1e8
font_02_sfnt_off00011d67.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11D67 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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