Malicious PDF — malware analysis report

Static analysis result for SHA-256 9c6819f2dd0d9783…

MALICIOUS

PDF

78.9 KB Created: 2021-09-08 19:19:42 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: 1b0b26138477ba58c132ee4f9e3c59d7 SHA-1: 0405a7f4bb73b5cc53ad2abf26787d3fe89dd6a1 SHA-256: 9c6819f2dd0d9783672c7b03c3a3af998a7850c9e57c62e0bebb1a511d68cc2f
96 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file contains a large number of embedded URLs, many of which point to compromised or disposable hosting services. The heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' indicates that the PDF is designed as a link farm, likely for SEO manipulation or to distribute malicious content. The ML classifier strongly flagged this PDF as malicious, supporting the assessment of a malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

Heuristics 5

  • 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://coretry.ru/uplcv?utm_term=iit+jee+maths+syllabus+2019+pdf PDF link annotation
    • http://tokyoto.pl/UserFiles/file/45685951231.pdfIn PDF document text
    • http://mastervin.ru/files/file/89577982440.pdfIn PDF document text
    • http://monthclean.com/uploads/files/202109031531033931.pdfIn PDF document text
    • http://www.valathors.com/ckfinder/userfiles/files/joxesule.pdfIn PDF document text
    • https://maritime-models.com/userfiles/file/24835673347.pdfIn PDF document text
    • https://thepainter.asia/upload/files/84035715706.pdfIn PDF document text
    • http://tw-tms.com/uploadpic/xw/files/68597301760.pdfIn PDF document text
    • https://mmgrowersg.com/ckfinder/userfiles/files/10730933212.pdfIn PDF document text
    • http://hocomesun.com/upload/batejitawipudiden.pdfIn PDF document text
    • http://serendipityorlando.com/wp-content/plugins/formcraft/file-upload/server/content/files/1612f84bce065c---30793418639.pdfIn PDF document text
    • https://armagedonspedycja.pl/files/file/38731205002.pdfIn PDF document text
    • https://belgradenightlife.info/wp-content/plugins/super-forms/uploads/php/files/url6a2vgh7fs94m0c8d1tkrkor/19060909075.pdfIn PDF document text
    • http://ylpqzl.com/ckfinder/userfiles/files/40688144791.pdfIn PDF document text
    • http://www.belladermeestetica.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/161317040b6ac0---94905448132.pdfIn PDF document text
    • https://lomasdelaweb.com/userfiles/2008.09/file/zepolimaguxomimikavexaxe.pdfIn PDF document text
    • https://psg66.ru/admin/ckfinder/userfiles/files/99260810042.pdfIn PDF document text
    • http://chinalabware.ru/d/files/vodutexatafemajuk.pdfIn PDF document text
    • https://www.willmarshelter.com/ckfinder/userfiles/files/loworovutanixobebu.pdfIn PDF document text
    • http://kripasec.com/userfiles/file/92018610626.pdfIn PDF document text
    • http://mbfeed.vn/upload/files/melotuzovefim.pdfIn PDF document text
    • https://glearningsolutions.com/userfiles/files/21221198923.pdfIn PDF document text
    • http://saringkarnwood.com/UserFiles/file/zaxubedejimofi.pdfIn PDF document text
    • https://patoman.ro/ckfinder/userfiles/files/36163922427.pdfIn PDF document text
    • http://qishuochem.com/siicea/userfiles/file/29874642242.pdfIn PDF document text
    • https://mlbcsimleague.com/ckfinder/userfiles/files/89387726014.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_off0000cbca.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCBCA 18164 bytes
SHA-256: 198c11dc2a164799e97e401d7d236753be0bfdcc4e6ada5cfd0e4297f0925960
font_01_sfnt_off0000fb18.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFB18 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0001132f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1132F 11336 bytes
SHA-256: 31da9ec7dcecf34a67e41b80d1426ae75472229010a98164c91c8fe3dc0df580