Malicious PDF — malware analysis report

Static analysis result for SHA-256 528085aa083405d5…

MALICIOUS

PDF

83.4 KB Created: 2021-07-07 00:32:49 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-13
MD5: 9199c1d2416ac108ce852205528e9c9c SHA-1: 0b14a6a418292c5e39e7de130f123948c32b4064 SHA-256: 528085aa083405d535974f2f9e6be5499a3fc877b7d83d6d8915324236302633
96 Risk Score

Malware Insights

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

The PDF contains a large number of links, many pointing to compromised WordPress sites and disposable hosting, indicating a link farm. The ML classifier strongly flagged this PDF as malicious. While no scripts were extracted, the structure and numerous external links suggest it's designed to redirect users to potentially harmful content or exploit kits.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9955

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://www.dyna-tech.nl/wp-content/plugins/formcraft/file-upload/server/content/files/160b093d5ec9cb---36249431388.pdf In PDF document text
    • https://patoman.ro/ckfinder/userfiles/files/pesiganakus.pdfIn PDF document text
    • https://ijpdua.com/contents//files/23933501340.pdfIn PDF document text
    • https://ccskin.com/geektic/files/66326484450.pdfIn PDF document text
    • https://dolphinsolutions.net/ckfinder/userfiles/files/balabagigugeli.pdfIn PDF document text
    • http://limpiasol.com/wp-content/plugins/formcraft/file-upload/server/content/files/160afb73f69228---bikomexojoxalozezepinebu.pdfIn PDF document text
    • http://www.sunarsurdurulebilir.com/wp-content/plugins/super-forms/uploads/php/files/drof0hdb02u1hskehla2m9rb80/bonezoboworanenilevo.pdfIn PDF document text
    • http://smartcookieacademy.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606f41787dad0---tojukuvuzatodezov.pdfIn PDF document text
    • http://www.holzbau-hoelzl.at/wp-content/plugins/formcraft/file-upload/server/content/files/16075e1538bdb4---baxarolovug.pdfIn PDF document text
    • https://f1com.ge/wp-content/plugins/super-forms/uploads/php/files/05c67a5bb940047277cab77055cfd6c9/97621848036.pdfIn PDF document text
    • http://stroynerud-sm.ru/wp-content/plugins/formcraft/file-upload/server/content/files/160c089e829616---dexizibu.pdfIn PDF document text
    • http://www.itbaloch.com/wp-content/plugins/formcraft/file-upload/server/content/files/16091d901ef956---99523866796.pdfIn PDF document text
    • http://mobydick-band.de/fckdata/file/34292685841.pdfIn PDF document text
    • http://lichnyiybrand.ru/wp-content/plugins/formcraft/file-upload/server/content/files/160c2e47973a6a---ximagidetumaxawaguzabukin.pdfIn PDF document text
    • https://qamarapps.com/wp-content/plugins/formcraft/file-upload/server/content/files/160aa0e5688527---18689213043.pdfIn PDF document text
    • http://trans-serwis.com/userfiles/file/sariropowiz.pdfIn PDF document text
    • https://autotrilogy.com/wp-content/plugins/super-forms/uploads/php/files/30eaab0195c65328d88c2e96f5fc7c13/51276784881.pdfIn PDF document text
    • https://mariellatriolo.it/public/file/70365778471.pdfIn PDF document text
    • http://basyapiemlak.com/yukleme_klasoru/userfiles/file/kovofep.pdfIn PDF document text
    • http://adria-ex.com/images/blog//file/gojeg.pdfIn PDF document text
    • http://escolacaritas.com/wp-content/plugins/formcraft/file-upload/server/content/files/16082433f45361---4683093804.pdfIn PDF document text
    • https://fajanav.com/aym_image/files/judilexidar.pdfIn PDF document text
    • https://jamiatulbanat.in/wp-content/plugins/formcraft/file-upload/server/content/files/1607b794dd0d78---33455385755.pdfIn PDF document text
    • http://akicgiyim.com/userfiles/file/18278433958.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/1xuhb7AK25c/uplcv?utm_term=cbse+last+year+question+paper+class+12PDF 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_off0000e23b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE23B 11072 bytes
SHA-256: c78c11ec86d61f8d8719de9230acfe7ff8acd8b895300940bad3129621b9a170
font_01_sfnt_off0000fc11.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFC11 16860 bytes
SHA-256: ed37c407735502e544e322afbac6854a45c473b02048e434732e8a6a3f6eeb8c
font_02_sfnt_off0001280f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1280F 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1