Malicious PDF — malware analysis report

Static analysis result for SHA-256 1a18fd8393b7586f…

MALICIOUS

PDF

69.4 KB Created: 2021-09-28 04:30:20 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: b439bca3571d0d5bdae0fb23eb498db0 SHA-1: 74b778b772685b5263050d1d43ba124e3d4b30d1 SHA-256: 1a18fd8393b7586f62536526ad8977ea2420a23503278569bea4ff26252fddb0
96 Risk Score

Malware Insights

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

The PDF contains a significant number of links pointing to external PDF files hosted on various domains, with several heuristics indicating a link farm pattern on compromised CMS uploads or disposable hosting. The ML classifier also flagged this PDF as malicious with high confidence. While no scripts were extracted, the structure suggests a malicious intent to redirect users to potentially harmful content, possibly for SEO poisoning or further distribution.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9954

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 http://btsoft.vn/uploads/files/bejilagemabonufojibojeruv.pdf In PDF document text
    • https://mkting.com.co/wp-content/plugins/super-forms/uploads/php/files/90a2000c28f8c0853f245a7b32136b9a/bewunokazosuribedixime.pdfIn PDF document text
    • http://sladkiy-ostrov.ru/userfiles/files/82916272168.pdfIn PDF document text
    • http://infosierra.es/images/editor/71406957368.pdfIn PDF document text
    • https://hotelite.in/userfiles/file/zogitupafe.pdfIn PDF document text
    • https://mandarinusa.com/userfiles/file/1630737209.pdfIn PDF document text
    • http://webursitet.org/Files/file/pedesutunatarufazirom.pdfIn PDF document text
    • http://www.maderas-navarro.com/ckfinder/userfiles/files/xinotufato.pdfIn PDF document text
    • https://laxmigrouppune.com/wp-content/plugins/super-forms/uploads/php/files/9b2800958e3a4eea43feb2e31ad504f4/78281157716.pdfIn PDF document text
    • https://ww150007.linebot.net/upfile/files/20210926223708.pdfIn PDF document text
    • https://sayurmateng.com/contents/files/lolirukufujudusigan.pdfIn PDF document text
    • http://starcity-vinhomes.vn/app/webroot/img/files/jojafuzadugedaladubesir.pdfIn PDF document text
    • https://elsadaulte.com/ckfinder/userfiles/files/xazamukinijilovavunupox.pdfIn PDF document text
    • http://www.cuerpomenteyespiritu.es/wp-content/plugins/formcraft/file-upload/server/content/files/161343220dff77---rorasezozasones.pdfIn PDF document text
    • https://kawanmto.org/contents/files/48504768544.pdfIn PDF document text
    • http://bolshunoff.ru/images/wysiwyg/file/zaniwolazonogekimuva.pdfIn PDF document text
    • https://dmitrovka-zn.ru/admin/ckfinder/userfiles/files/36375514839.pdfIn PDF document text
    • https://kabelkyaobuv.sk/editor_uploads/files/vadesawigej.pdfIn PDF document text
    • http://jumpstart.mobi/ckfinder/userfiles/files/janojomexaxadulena.pdfIn PDF document text
    • http://akcihlar.cz/userfiles/file/86996795585.pdfIn PDF document text
    • http://boldino-hotel.com/ckfinder/userfiles/files/2453608859.pdfIn PDF document text
    • https://ddnepal.com/assets/userfiles/files/vifomi.pdfIn PDF document text
    • http://quickfix-poland.com/wp-content/plugins/formcraft/file-upload/server/content/files/16142dbc81b4e7---gibamiz.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/Om9ozkHLxGw/uplcv?utm_term=aesthetic+live+wallpaper+androidPDF link annotation
    • https://b2cdemo.tickets.com/content/files/fenomolopumorow.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_off0000afa7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xAFA7 10744 bytes
SHA-256: f83b7e2dd042e95b3c806ac7e0d0a2da7ec5b6d40560a20fa25548295eab041d
font_01_sfnt_off0000c867.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC867 14948 bytes
SHA-256: cd7695a15a22b94c2fd16f274d932567a2fa1c78149813be44d7fbe10f48695c
font_02_sfnt_off0000ee5c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEE5C 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1