Malicious PDF — malware analysis report

Static analysis result for SHA-256 521bec8162358fee…

MALICIOUS

PDF

76.6 KB Created: 2021-08-29 07:07:06 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: a69d650ffd17fe8a9a79e8d736b96725 SHA-1: 0cdad26cc4b9bb30961e50f1e8a7e72b914bc4e1 SHA-256: 521bec8162358fee28f577315229c77ad5a55e9b3517cf720a67235d6b3bc367
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample was flagged by ClamAV as Pdf.Phishing.Trojan and an ML classifier indicated a high probability of maliciousness. It contains embedded JavaScript, which is often used to exploit PDF vulnerabilities or redirect users. The PDF also functions as a link farm, pointing to numerous external URLs hosted on various domains, some of which appear to be compromised WordPress sites, increasing the likelihood of a phishing or malware distribution campaign.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9989

Heuristics 7

  • 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.
  • 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 https://pmms-online.com/assets/file/givemimowuvepuku.pdf In PDF document text
    • http://kazenergy.kz/wp-content/plugins/formcraft/file-upload/server/content/files/1609b90582fa23---4812576172.pdfIn PDF document text
    • http://qiangka.com/ckfinder/userfiles/files/4799732538.pdfIn PDF document text
    • http://bkdesign.ee/userfiles/file/gimawanuzojibuvajuxipaxo.pdfIn PDF document text
    • https://retentionstudentexperience.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b9c84e63db2---14708662651.pdfIn PDF document text
    • http://noithatphathuy.com/Images_upload/files/9551666616.pdfIn PDF document text
    • https://grupo.iberia.es/js/ckfinder/userfiles/files/89776336709.pdfIn PDF document text
    • http://labotinnghia.com/img/files/5046982560.pdfIn PDF document text
    • http://dkyangmei.com/uploadfile/file/2021070601291473499.pdfIn PDF document text
    • http://hyundaidongdo3s.com/images/files/pinerenupigeruvudaxax.pdfIn PDF document text
    • http://weiken-rc.com/upload/files/21089351682.pdfIn PDF document text
    • https://hafa-verein.de/wp-content/plugins/super-forms/uploads/php/files/78b30850c6c9402b0927ff7a98e35b90/85560241297.pdfIn PDF document text
    • http://fpsh1980.com/clients/7/7d/7de5299bd6bdc19cdd6b275c058e9c4a/File/posusufebudozejubikuteb.pdfIn PDF document text
    • https://hmjrgoldhockey.org/wp-content/plugins/super-forms/uploads/php/files/4a217c95346031ae401ed244a275ac14/xuxudafogoluj.pdfIn PDF document text
    • https://didacostruzioni.it/userfiles/file/32463064779.pdfIn PDF document text
    • http://scissortailfarms.com/wp-content/plugins/formcraft/file-upload/server/content/files/160d6b7c093cc8---sotapuxuliluvisal.pdfIn PDF document text
    • https://evocative.ru/wp-content/plugins/formcraft/file-upload/server/content/files/1608b3ae45ac11---mibozimobadolo.pdfIn PDF document text
    • https://zweiund40.com/wp-content/plugins/super-forms/uploads/php/files/k4o0ev0lbg8sde20j81ev5qagm/9502567634.pdfIn PDF document text
    • http://idroter.org/userfiles/files/tixuziruger.pdfIn PDF document text
    • http://www.peritaonline.es/ckfinder/userfiles/files/tarizajugebavukatir.pdfIn PDF document text
    • https://nadinerogger.ch/userfiles/files/werunuxuse.pdfIn PDF document text
    • http://drairtools.com/ckfinder/userfiles/files/21861646992.pdfIn PDF document text
    • http://ziepniekkalns.lv/wp-content/plugins/formcraft/file-upload/server/content/files/160814b97627e3---67650241567.pdfIn PDF document text
    • http://www.icodar.com/wp-content/plugins/formcraft/file-upload/server/content/files/160747bb08feb8---kegeteweris.pdfIn PDF document text
    • https://www.democratum.com/wp-content/plugins/super-forms/uploads/php/files/2b2bdbe2c8ac3e23f78e98b1065314d6/78476542656.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/1KS0DP0cxss/uplcv?utm_term=replace+color+in+an+imagePDF 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_off0000c843.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC843 17048 bytes
SHA-256: 7859c4e07e29a9235e95bf8c855faaa395e3ab44300e612b941923be294b6a93
font_01_sfnt_off0000f432.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF432 10496 bytes
SHA-256: 5af6533cc2b58afa12015974ce29c73812d95e2a3889af4a5767eca5a528785d
font_02_sfnt_off00010bf9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10BF9 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1