Malicious PDF — malware analysis report

Static analysis result for SHA-256 4b171323afebe41c…

MALICIOUS

PDF

89.4 KB Created: 2021-09-19 08:45:47 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: 3bfb5ebb3b66c38436d167126669c714 SHA-1: 6e140d63099187c53da01ee98b39faa012a47af2 SHA-256: 4b171323afebe41c810027801ff1a18d741b2a71af532eaecdc822a3b62df72b
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

This PDF file was identified as malicious by multiple heuristics, including a high-confidence ML classifier and ClamAV. It functions as a link farm, containing numerous embedded URLs pointing to various domains, some of which are associated with compromised CMS uploads or disposable hosting. The presence of an embedded JavaScript stream suggests an attempt to execute malicious code, likely to facilitate further exploitation or payload delivery.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9982

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://smidgel.ru/uplcv?utm_term=ui+system+android PDF link annotation
    • http://dooroc.com/tk/upload/file/14528540980.pdfIn PDF document text
    • https://konferencii.ru/js/ckfinder/userfiles/files/1266157282.pdfIn PDF document text
    • http://villkasz.hu/editor_up/fozubonefipevaruxivo.pdfIn PDF document text
    • https://rheinfurth.de/userfiles/file/tikofekun.pdfIn PDF document text
    • https://padservhosting.com/userfiles/file/todivak.pdfIn PDF document text
    • https://xn--z4qq44i.xn--kpry57d/upload/actfiles/topuzeses.pdfIn PDF document text
    • http://zezoalza.com/ckupload/files/76762523528.pdfIn PDF document text
    • https://fresh-cherries.com/ckfinder/userfiles/files/37810458384.pdfIn PDF document text
    • https://www.penyembuhanholistikreiki.com/wp-content/plugins/formcraft/file-upload/server/content/files/16139f8c2e9bf1---61992663653.pdfIn PDF document text
    • http://ciarajewellery.com/editor_upload/file/10511258875.pdfIn PDF document text
    • https://thailonghoang.vn/upload/files/bewujawizomomozotemi.pdfIn PDF document text
    • http://jawarakreasi.com/file/52785889983.pdfIn PDF document text
    • https://jensbrode.de/files/file/33925041886.pdfIn PDF document text
    • http://raczcsalad.hu/files/43013030463.pdfIn PDF document text
    • http://www.stratcareerservices.com/wp-content/plugins/formcraft/file-upload/server/content/files/16146c5987b92f---58805610096.pdfIn PDF document text
    • https://www.habitat-morvan.fr/ckfinder/userfiles/files/28524722150.pdfIn PDF document text
    • http://sirinthepgroup.com/userfiles/file/kulalazarumiruxikuwudeku.pdfIn PDF document text
    • http://elmbbq.com/uploads/files/98236754548.pdfIn PDF document text
    • http://zzzwchem.com/upload/files/13662287883.pdfIn PDF document text
    • https://sumangold.net.vn/wp-content/plugins/super-forms/uploads/php/files/trtjl5lv9mvdvalajh28viop17/lupabum.pdfIn PDF document text
    • https://embassyinvietnam.com/webroot/img/files/26299343603.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_off0000f7c2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF7C2 18676 bytes
SHA-256: 620aa403b1147dc31ed3938ae167eb1a3f15dc206d08fb834c151d102f3a0226
font_01_sfnt_off00012863.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12863 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0001407a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1407A 10484 bytes
SHA-256: b5a55c81c82ea4f560b660f335c51682aabb4eef628ce0118ef57cac36b296d0