Malicious PDF — malware analysis report

Static analysis result for SHA-256 5e27b574bf1ab669…

MALICIOUS

PDF

73.5 KB Created: 2021-09-18 13:13:42 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-25
MD5: 83cb94a01bc697703de5d5f0ee7ab6a0 SHA-1: d49053bbb71c57d713d5537ee7278b814f037a11 SHA-256: 5e27b574bf1ab66997447e928d3d9b52fd3704d568dc8195e7945e93ba5e403c
156 Risk Score

Malware Insights

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

The PDF was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. It contains numerous embedded URLs, many of which point to compromised or disposable hosting, suggesting a link farm designed to distribute malicious content or phish users. The `wkhtmltopdf` authoring application and the presence of multiple PDF link farm heuristics further support this assessment.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9951

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://ebonit.light.bg/includes/libs/ckfinder/userfiles/files/wuzosi.pdf In PDF document text
    • http://xn--80aab8aioy.xn--p1ai/userfiles/file/8277990588.pdfIn PDF document text
    • http://balassalaw.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/motawovejasapodomuso.pdfIn PDF document text
    • https://xlux.vn/wp-content/plugins/super-forms/uploads/php/files/00n9b098igmednuoemfc5qm7cc/jovadesaxoridokivujexiki.pdfIn PDF document text
    • http://problemconsulting.com/img/download/files/93889875782.pdfIn PDF document text
    • http://ttccid.com/userfiles/files/novewupufapinafetot.pdfIn PDF document text
    • https://rpdev.org/ckfinder/userfiles/files/piwasanowifotabad.pdfIn PDF document text
    • http://stefani.cz/fck/file/96762583743.pdfIn PDF document text
    • http://hublihorse.com/uploads/userfiles/files/sidulo.pdfIn PDF document text
    • http://salamatekhanevadeh.ir/ckeditor/files/files/talozifuvoziv.pdfIn PDF document text
    • https://tedvandergulik.nl/userimages/file/37884264980.pdfIn PDF document text
    • https://123kozijnofferte.nl/wp-content/plugins/super-forms/uploads/php/files/257b6bd7383ade81b1c8116c2f71edd8/luxelekeforizije.pdfIn PDF document text
    • http://luisacortesearchitetto.it/userfiles/files/jinexepetuxusi.pdfIn PDF document text
    • http://hndgyl.com/v15/Upload/file/202198124847781.pdfIn PDF document text
    • http://www.koeru.eu/failid/file/luvumanutenale.pdfIn PDF document text
    • https://pakistanchristiancongress.org/userfiles/file/tasurubis.pdfIn PDF document text
    • http://sieuthibongda.net/ckfinder/userfiles/files/pedaluluvaz.pdfIn PDF document text
    • https://www.ideaklinikkadikoy.com/wp-content/plugins/formcraft/file-upload/server/content/files/16131b0829a300---45213910475.pdfIn PDF document text
    • http://divyabodhanam.org/userfiles/file/lugituxavifina.pdfIn PDF document text
    • https://baust.edu.bd/app/webroot/ckfinder/userfiles/files/gilatikofutebe.pdfIn PDF document text
    • http://biurod9.pl/public/userfiles/file/samarafufofejabirinaxag.pdfIn PDF document text
    • http://remproekt-m.ru/admin/ckfinder/userfiles/files/kuxigejosapekimozakogip.pdfIn PDF document text
    • http://zoltysnieg.pl/pliki_wyswig/files/13128174667.pdfIn PDF document text
    • http://transgusto.ch/userfiles/file/sibinenika.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/A3Ryygt5BCM/uplcv?utm_term=the+game+production+handbook+3rd+edition+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_off0000b860.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB860 17756 bytes
SHA-256: b70e087a16ca9b5f0f666227ea6f08b88e9e97fda466f0329524d6a842837db2
font_01_sfnt_off0000e623.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE623 11320 bytes
SHA-256: 17a92e4368a5bca9962ee054ffbd4235d1ac933075e200dea2e6e756ef1b1403
font_02_sfnt_off0001002b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1002B 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1