Malicious PDF — malware analysis report

Static analysis result for SHA-256 dbf4d48e654f5101…

MALICIOUS

PDF

81.0 KB Created: 2021-09-20 05:45:15 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 23aacf0fdf09a66c332262cbb463bafc SHA-1: 07a69b06e8fdfde411c30089e235c6d22fe5a3de SHA-256: dbf4d48e654f51010d6f8930523307e182f54606c3f37c66a71e736c842439d3
96 Risk Score

Malware Insights

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

The PDF contains numerous links to other PDF files hosted on various domains, many of which appear to be compromised CMS upload directories. The ML classifier strongly indicates maliciousness, and the link farm behavior suggests an attempt to manipulate search engine results or distribute further malicious content. No scripts were extracted, but the structure and URL patterns are indicative of a malicious distribution or SEO poisoning campaign.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9968

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://btsis.com/upload/ckfinder/files/sawunolemawusurusovinazen.pdf In PDF document text
    • https://haisanquangninh.org/data/dulieu/files/lirur.pdfIn PDF document text
    • http://langeline.com/ckeditor/upload/files/54184955325.pdfIn PDF document text
    • http://dgjst.com/upfile/file/14217621297.pdfIn PDF document text
    • http://beijingteye.com/upload/files/46758319665.pdfIn PDF document text
    • http://xn--k1akb4c.xn--p1ai/userfiles/file/ramamukakawi.pdfIn PDF document text
    • https://xlux.vn/wp-content/plugins/super-forms/uploads/php/files/414cn7jmanisu83tcg1b5fnj6t/63534923951.pdfIn PDF document text
    • https://kar360.com/resimler/files/39917977556.pdfIn PDF document text
    • http://schodylux.pl/userfiles/file/53209118887.pdfIn PDF document text
    • http://gavinlawoffice.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/nedage.pdfIn PDF document text
    • https://millinerandassoc.com/files/file/32018435512.pdfIn PDF document text
    • http://emiem.pl/public/upload/ckfinder/userfiles/files/jaxuza.pdfIn PDF document text
    • http://premiumresourcing.com/wp-content/plugins/formcraft/file-upload/server/content/files/16144cedbe48e4---19201057601.pdfIn PDF document text
    • https://ncfouting.com/wp-content/plugins/formcraft/file-upload/server/content/files/16140d78e3b791---godoforupop.pdfIn PDF document text
    • http://mim2010.ru/userfiles/file/pulisodiwomupugum.pdfIn PDF document text
    • https://kabelkyaobuv.sk/editor_uploads/files/biforuzitetinog.pdfIn PDF document text
    • https://mcq-exambd.com/app/webroot/ckfinder/userfiles/files/kemone.pdfIn PDF document text
    • http://busangh.com/attfile/fckimg/file///20210914175617_1054596774.pdfIn PDF document text
    • http://partnercable.com/files/mamubenekonaj.pdfIn PDF document text
    • http://mnwebdesign.dk/userfiles/file/gaveda.pdfIn PDF document text
    • http://ficfart.org/userfiles/file/wigonokepariwifoti.pdfIn PDF document text
    • http://cheapneasytrafficschool.com/CheapNEasyTrafficSchool/pa/trainstation/uploads/image/file/74391747151.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/A3Ryygt5BCM/uplcv?utm_term=pc+hardware+monitor+androidPDF 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_off0000d8c0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD8C0 17868 bytes
SHA-256: 0c9d598d61c4401704294253671c37189e9d6b78188091def7fc756cbdbf3960
font_01_sfnt_off00010709.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10709 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00011f20.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11F20 10508 bytes
SHA-256: e5af343f2e16948f05ffca2a4e6397ca3079d1f43be43c464c90546f8266a556