Malicious PDF — malware analysis report

Static analysis result for SHA-256 81a73310f6a80620…

MALICIOUS

PDF

76.6 KB Created: 2021-10-01 12:11:36 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-23
MD5: 314cff89660d199d44d74a8fa1f95051 SHA-1: 62d5db1b654c697529af3811d4f8da7b7792df54 SHA-256: 81a73310f6a8062004deb9390b524ce7d8eac0a7421ae048b11ff8b008d34461
156 Risk Score

Malware Insights

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

The PDF file was flagged by ClamAV as Pdf.Phishing.Trojan and a machine learning classifier indicated a high probability of maliciousness. Several heuristics indicate the PDF functions as a link farm, pointing to various domains, some of which are hosted on compromised CMS uploads. The embedded URLs suggest an attempt to redirect users to potentially malicious content, aligning with phishing or SEO abuse tactics.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9985

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 http://brcassociati.com/userfiles/files/fonezatajerokelawinun.pdf In PDF document text
    • http://partnercable.hu/files/nupebiwifuvapigotojo.pdfIn PDF document text
    • https://ibliberia.com/ckfinder/userfiles/files/wevogurolokegimefesi.pdfIn PDF document text
    • http://popnmusic.fr/userfiles/file/mozetewuvaraxob.pdfIn PDF document text
    • https://cvsc.co/userfiles/file/wetubifo.pdfIn PDF document text
    • https://techlan.pl/files/file/bubepogisu.pdfIn PDF document text
    • https://cobaltinc.org/userfiles/file/bawiwularolilojejufeluv.pdfIn PDF document text
    • http://plaschke-partner.com/uploaded/file/26884259838.pdfIn PDF document text
    • http://adacu.org/userfiles/file/20210927211747.pdfIn PDF document text
    • https://www.syria-report.com/sites/all/libraries/ckfinder/userfiles/files/benupotapip.pdfIn PDF document text
    • http://pevak.info/UserFiles/File/ralewetalemikuliderolelad.pdfIn PDF document text
    • http://locthanhroyal.com/upload/files/32617963269.pdfIn PDF document text
    • https://borderpak.com/wp-content/plugins/super-forms/uploads/php/files/9d38cf71aa9ba62aa4ee476aba877faa/dojoxozuzigozebaxolon.pdfIn PDF document text
    • http://naoshima-tours.com/images/blog/file/73999094040.pdfIn PDF document text
    • https://pyhm.ca/wp-content/plugins/super-forms/uploads/php/files/v62bsd7b86p96bg2dm7uqfq4sm/99509684895.pdfIn PDF document text
    • http://galtex.sk/storage/file/87786075424.pdfIn PDF document text
    • http://www.olympussverige.se/wp-content/plugins/super-forms/uploads/php/files/5ibojpae3tbcn8som4cdhpbb65/84286150213.pdfIn PDF document text
    • http://danchrisjewelry.com/userfiles/file/gakifem.pdfIn PDF document text
    • https://ebal.ro/app/webroot/files/userfiles/files/14419298626.pdfIn PDF document text
    • https://aldea.work/wp-content/plugins/super-forms/uploads/php/files/c9ebfb2098acd71d18ba9ac5386578a0/49838015071.pdfIn PDF document text
    • https://www.sidertest.it/wp-content/plugins/formcraft/file-upload/server/content/files/16155d029c9236---61934641487.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/6naE_Nh8_CY/uplcv?utm_term=brian+tracy+books+in+tamil+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_off0000bdd9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBDD9 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000d5eb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD5EB 20432 bytes
SHA-256: 9ddcc1eee64cb153ffc975cc0fd45025992bc46f62ae5cb55d7cea997ce36184
font_02_sfnt_off00010b32.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10B32 11048 bytes
SHA-256: 6508325196fb56b66e4db360a63594e5f1ac01f228022b3469ca55926fe580e3