Malicious PDF — malware analysis report

Static analysis result for SHA-256 528a188808a81cd5…

MALICIOUS

PDF

70.4 KB Created: 2021-09-25 00:21:58 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-24
MD5: 90b5944457dd5b00002dfebb70450868 SHA-1: b7c66e4c66cd69d69ab2a7c7de04c15047acbcd4 SHA-256: 528a188808a81cd5835f59d2681a29bd9c116b3aead2901ff979a5948889bb37
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a PDF containing embedded JavaScript, which is a common technique for executing malicious code. It also features a link farm pointing to multiple domains, many of which are hosted on disposable or compromised infrastructure, suggesting an attempt to distribute phishing content or malware. The ClamAV detection and ML classifier further support its malicious nature.

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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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://4yoga.by/pics/files/32287237410.pdf In PDF document text
    • http://makesomenoise.hu/upload/file/nebapezamedirasup.pdfIn PDF document text
    • https://galedo.cz/www/data/cms_files/files/balevopijerefa.pdfIn PDF document text
    • https://classconnbio.com/img-jacson/files/kibipejokidikete.pdfIn PDF document text
    • http://artpolinakuzina.ru/pict/file/kifakoxiweze.pdfIn PDF document text
    • http://srihemkuntschoolint.com/slbdavbatala/userfiles/file/vujoza.pdfIn PDF document text
    • https://investincarpathians.eu/app/webroot/media/files/folowaxopajezevaru.pdfIn PDF document text
    • https://hargagila.com/uploads/image/files/8374339353.pdfIn PDF document text
    • https://www.physioaktivkramer.de/wp-content/plugins/formcraft/file-upload/server/content/files/1612effaeae285---zadoxawika.pdfIn PDF document text
    • http://kurier48.pl/files/userfiles/file/81986709952.pdfIn PDF document text
    • http://sinostandards.net/upload/files/62785741669.pdfIn PDF document text
    • http://a-mega.ua/images/uploads/file/sukiju.pdfIn PDF document text
    • http://doggystylzgrooming.com/admin/photos/file/ramerikoketok.pdfIn PDF document text
    • http://bephoangdung.vn/uploads/ckfinder/files/ludegifigetakote.pdfIn PDF document text
    • https://kabelkyaobuv.sk/editor_uploads/files/19431766781.pdfIn PDF document text
    • https://ferropula.hr/files/85629827901.pdfIn PDF document text
    • http://immopolignano.lu/images/kawaworul.pdfIn PDF document text
    • https://catherinehourihan.art/wp-content/plugins/super-forms/uploads/php/files/4c335ba5c6bc240b6598c8954c52ebed/64806519400.pdfIn PDF document text
    • https://www.oasipizza.it/wp-content/plugins/formcraft/file-upload/server/content/files/1613a1febea81d---82345240468.pdfIn PDF document text
    • http://dom-2000.ru/ckfinder/userfiles/files/4069676989.pdfIn PDF document text
    • https://shindah.com/images/ckeditor_img/files/70971641654.pdfIn PDF document text
    • https://aljuboori.com/userfiles/files/xowamiwitike.pdfIn PDF document text
    • http://greatwalledmond.com/ckfinder/userfiles/files/fanasawetipujumoxulopami.pdfIn PDF document text
    • http://strojsteel.cz/webpagebuilder/ckfinder/userfiles/files/41705465294.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/BkSY9tpko7c/uplcv?utm_term=housecall+free+online+scanPDF link annotation
    • https://www.assessment.unibe.ch/app/webroot/js/ckfinder/userfiles/files/48910339442.pdfIn PDF document text
    • 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_off0000b3e9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB3E9 15152 bytes
SHA-256: 4bed01233649c6d82e934efbde8df007737e187c512977ecbc60dfbeb42f21c6
font_01_sfnt_off0000da75.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDA75 10324 bytes
SHA-256: a86cb6f9098e90dd179f5cd7904acc617b1f971a5319750ee26019a4f0bcd714
font_02_sfnt_off0000f1ce.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF1CE 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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