Malicious PDF — malware analysis report

Static analysis result for SHA-256 a23f581e3fec7349…

MALICIOUS

PDF

87.0 KB Created: 2021-07-01 00:55:41 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: 81fd5d49859e594ee239831ec592fec1 SHA-1: 34321bf16a2b2eeb79f988d2f0373786a9c70804 SHA-256: a23f581e3fec73497ca66aa8260eedb613d4b8cae90b79d46d1aadfb58b01e43
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF contains numerous embedded URLs, many of which point to compromised CMS upload directories or are part of a link farm. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for phishing or distributing further malware. No scripts were extracted, and the document body was unreadable, but the URL structure and heuristic firings are sufficient to assess the attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9991

Heuristics 6

  • 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.
  • 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://bizdrive.nl/wp-content/plugins/formcraft/file-upload/server/content/files/1/16073023b832fa---75171525079.pdf In PDF document text
    • https://www.jscorporation.co.in/wp-content/plugins/formcraft/file-upload/server/content/files/160903d8a79350---45721794023.pdfIn PDF document text
    • http://www.gaviprintpack.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609deb8a04e66---58973605345.pdfIn PDF document text
    • http://bestforfishing.com/wp-content/plugins/super-forms/uploads/php/files/e59a5cf0de79e1bee808c0a9e1c313c5/sulubijefowivu.pdfIn PDF document text
    • http://greenld.com/userfiles/65687933755.pdfIn PDF document text
    • http://booklandbooks.com/userfiles/file/79563159179.pdfIn PDF document text
    • https://dadesigning.com/daduserfiles/files/69203593732.pdfIn PDF document text
    • https://wacee.net/wp-content/plugins/formcraft/file-upload/server/content/files/160b9f6ef47b2e---bunaxorujavumedomemar.pdfIn PDF document text
    • https://skvely-kup.cz/files/file/14177244675.pdfIn PDF document text
    • http://www.neslihanonur.com/wp-content/plugins/super-forms/uploads/php/files/40fc22c157333aab7944ba331c159631/84726859755.pdfIn PDF document text
    • http://teusz.pl/UserFiles/file/67952087951.pdfIn PDF document text
    • https://bikeid.net/ckfinder/userfiles/files/nusajivubekifiponigina.pdfIn PDF document text
    • https://beaszemin.com/files/60864041751.pdfIn PDF document text
    • http://obasekiestates.com/UserFiles/file/23715603917.pdfIn PDF document text
    • https://areshin.ru/wp-content/plugins/super-forms/uploads/php/files/b1901593d3c3b9afe64f7973eda6f4ce/4056055990.pdfIn PDF document text
    • https://bursaceviritercume.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b21fec8e551---mizojumipipevubon.pdfIn PDF document text
    • https://juhaszautovill.hu/userfiles/file/temisaxebut.pdfIn PDF document text
    • http://grani-tonkogo-mira.ru/wp-content/plugins/super-forms/uploads/php/files/33bb7acb81c58e4db82253d3464ed125/juzolokab.pdfIn PDF document text
    • http://mextro.de/upload/files/vusivujuwarifenonobiponim.pdfIn PDF document text
    • http://www.phonefixcomo.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606f13947d44c---16242367705.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/S30rS-6n6vg/uplcv?utm_term=different+types+of+letters+in+english+pdfPDF 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_off0000f196.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF196 10728 bytes
SHA-256: 5479c3089696465f47d64aa6b679077264e123ce66779ebe78f7adf7d21c80c4
font_01_sfnt_off000109f3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x109F3 17256 bytes
SHA-256: 9c15b460254222a6ea7c822da296f59657c709e1e10c5c0f35622689220ee02f
font_02_sfnt_off000136e1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x136E1 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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