Malicious PDF — malware analysis report

Static analysis result for SHA-256 13c8733c58ccca71…

MALICIOUS

PDF

84.0 KB Created: 2021-09-03 04:26:58 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-05
MD5: e25e01b7c98b2f9159d29dd64e12b309 SHA-1: e506aeabd588a53b9d3d2b1afd27db91060277da SHA-256: 13c8733c58ccca71e9803ee700c460cf702baa8bc20be600819bb54e87260d8b
176 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous links to compromised WordPress upload directories, indicating it functions as a link farm to distribute malicious content. The ClamAV detection and ML classifier strongly suggest malicious intent, likely phishing or malware delivery. Although no scripts were explicitly extracted, the PDF structure and embedded URLs are indicative of a malicious document designed to lure users to compromised sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9981

Heuristics 7

  • 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.
  • Callback phishing phone lure medium SE_CALLBACK_LURE
    Document asks the user to call a phone number in billing, refund, subscription, fraud, or security context — consistent with callback phishing or tech-support scam patterns. Suppressed for legitimate-issuer (IRS/gov/official-form) documents that carry no urgency or charge/dispute escalation.
  • 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://xn----8sbaavnccwq4am.xn--p1ai/wp-content/plugins/super-forms/uploads/php/files/e7334b817cf2981f7465fe5616a152b5/39732486753.pdf In PDF document text
    • https://www.intermediastudios.com.mx/wp-content/plugins/super-forms/uploads/php/files/58e658d1ea3d6fd83e00c7e8a9a75a86/88760683479.pdfIn PDF document text
    • https://cursosgratuitosonline.es/wp-content/plugins/super-forms/uploads/php/files/r7275qdrg1tk271enu4gj1e887/11229673126.pdfIn PDF document text
    • http://philippinesroadshow.com/wp-content/plugins/super-forms/uploads/php/files/bf509dfefe33126c66fb1dddc846634b/2011218031.pdfIn PDF document text
    • http://www.depomatrial.com/file/25972590855.pdfIn PDF document text
    • http://yatros.ro/wp-content/plugins/formcraft/file-upload/server/content/files/160a4868b22377---duwuxiwozupunusegibiti.pdfIn PDF document text
    • https://ventana-sur.com/wp-content/plugins/formcraft/file-upload/server/content/files/16076c34149469.pdfIn PDF document text
    • http://thegioituigiay.net/uploads/files/gojago.pdfIn PDF document text
    • http://rubensova16.cz/files/file/bojurivonesododol.pdfIn PDF document text
    • http://av-jet.ru/userfiles/file/vemexozetogatavusepadux.pdfIn PDF document text
    • http://www.gpe-el.pro/ckfinder/userfiles/files/tolewoladeganejuguwani.pdfIn PDF document text
    • http://www.kinoimaging.nl/wp-content/plugins/formcraft/file-upload/server/content/files/160a1436d5df02---rometekefipepo.pdfIn PDF document text
    • https://grand-forge.ru/wp-content/plugins/super-forms/uploads/php/files/e8969b4c711939883dc9790862c74e8b/xotixebemi.pdfIn PDF document text
    • http://sun-green.de/ckfinder/userfiles/files/safevepapi.pdfIn PDF document text
    • http://levne-pohary.cz/UserFiles/File/tozajenawupotelesudi.pdfIn PDF document text
    • http://luvnchrlysenglishtoys.com/clients/861429/File/musaduziviwu.pdfIn PDF document text
    • http://self119.net/upload/userfiles/2021/06/files/210614135149.pdfIn PDF document text
    • http://101eyewear.com/luutru/files/nosimotom.pdfIn PDF document text
    • https://harkakotony.hu/UserFiles/file/fotos.pdfIn PDF document text
    • http://asfalon.com/__files/file/puboxuxolusozun.pdfIn PDF document text
    • https://amezdigital.com/wp-content/plugins/super-forms/uploads/php/files/2f22d5105b70fa4b7d0548d9252f06ef/wuwigarejamalupejur.pdfIn PDF document text
    • https://hansenlight.com/UploadFile/files/jafepawuroxefavomex.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/YTWXjIUwRh0/uplcv?utm_term=2014+gmc+terrain+sle+owners+manualPDF 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_off0000e304.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE304 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000fb16.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFB16 17520 bytes
SHA-256: 5d1c6a5a6ab86356f143054a77a2e3058bf7b2248ee6c05acd8c5773797d53b7
font_02_sfnt_off000128a4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x128A4 11036 bytes
SHA-256: 0e5c326c426e75175c96ef46ac44db1bc8d0412bb0475158eb75e0fdf3cf9f35

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