Malicious PDF — malware analysis report

Static analysis result for SHA-256 c8a5782a2d13b5e4…

MALICIOUS

PDF

72.5 KB Created: 2021-09-08 03:50:14 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-05
MD5: 71899513de09414fa5adeb7764a4d3b6 SHA-1: a0b376b88dec09a9d62a7cc636f67e3ec29271ad SHA-256: c8a5782a2d13b5e40ed3ce8fe0c7d150b2a641037a5b5b3e7e44eafe277c4643
156 Risk Score

Malware Insights

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

The PDF contains a link farm pointing to numerous other PDF files hosted on various domains, many of which appear to be compromised CMS uploads. 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, so the attack pattern is inferred from the URL structure and heuristic firings.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9965

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://mattress-leader.com/media/91915872275.pdf In PDF document text
    • https://likeevent.it/writable/public/userfiles/file/51501966808.pdfIn PDF document text
    • https://amkboiler.com/wp-content/plugins/super-forms/uploads/php/files/173kftr8eb49h1jlslo7ojkdtq/57716536257.pdfIn PDF document text
    • http://komodovo.ru/upload_picture/jewonuvaforaguvoginot.pdfIn PDF document text
    • http://marketingnews.fr/images/file/5950671182.pdfIn PDF document text
    • https://regenerativetherapyforpain.com/wp-content/plugins/super-forms/uploads/php/files/d1fada7037be57f415142345d9ccc6de/korinematanodojudagip.pdfIn PDF document text
    • https://www.ideaklinikbursa.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607cc2bec83ea---87697298700.pdfIn PDF document text
    • https://www.icslights.com/wp-content/plugins/super-forms/uploads/php/files/04f84fa1bd05cae2281aebd9fb09bcb6/nefirogapeduki.pdfIn PDF document text
    • https://burstallconrad.com/editor_files/file/vumajutodataw.pdfIn PDF document text
    • https://drnanemilk.com/tctt/sites/aaa/file/bunutopukono.pdfIn PDF document text
    • http://notarbrazda.cz/userfiles/file/8397003039.pdfIn PDF document text
    • http://wdnederland.nl/file/pilinukakuz.pdfIn PDF document text
    • http://adaviestransportltd.com/userfiles/file/82630002113.pdfIn PDF document text
    • https://mercedesmazo.es/wp-content/plugins/formcraft/file-upload/server/content/files/16128e3ac5ec24---mopawidovawubobimu.pdfIn PDF document text
    • https://neoville.ru/wp-content/plugins/super-forms/uploads/php/files/9d55ab93ac5737b5b7417754575f3eab/wiwabanekijugawojiw.pdfIn PDF document text
    • http://salkim.com/userfiles/file/82035543739.pdfIn PDF document text
    • https://propage.q-cloud.net/upload/ckeditor/pages/files/kudapox.pdfIn PDF document text
    • http://altinay-law.com/images/file/sigorisarikubujuleja.pdfIn PDF document text
    • https://tectrongim.com/uploads/files/67531377984.pdfIn PDF document text
    • https://angkalaris.com/contents/files/jimasuzuwif.pdfIn PDF document text
    • http://bioscipublisher.com/files/upfiles/file/81979343530.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/LPIa9PGmDLg/uplcv?utm_term=regular+verbs+in+the+past+tense+worksheetPDF 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_off0000ba8b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBA8B 15784 bytes
SHA-256: 1c855bd13dedf710372d93c529868a4e77cb1e09b98c5a1b19d08209ac1ff9cf
font_01_sfnt_off0000e2c5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE2C5 11060 bytes
SHA-256: 957c43c59673aeefe2973ea131df91d96d8114627b3aff490defcb69e8cd5caa
font_02_sfnt_off0000fc53.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFC53 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1