Malicious PDF — malware analysis report

Static analysis result for SHA-256 b731387ac6bfab99…

MALICIOUS

PDF

85.9 KB Created: 2021-10-14 10:33:13 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-23
MD5: a51f6882c61be3bf681e9a590d504d86 SHA-1: 67814376bee1a17e536e847d2069f3216f6a086f SHA-256: b731387ac6bfab995c12d987b8a9e696ebb9c5a1f757105fdfb3210fe7b2cb74
164 Risk Score

Malware Insights

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

The PDF contains embedded JavaScript and multiple external URIs, some of which point to compromised WordPress sites and link farms. The ML classifier and ClamAV detection strongly indicate malicious intent, likely to exploit vulnerabilities or redirect users to phishing sites. The presence of JavaScript suggests an attempt to download and execute a second-stage payload.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9912

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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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://santiagoporter.com/js/ckfinder/core/connector/php/files/86896185694.pdf In PDF document text
    • https://vocembalo.ch/userfiles/file/sokuw.pdfIn PDF document text
    • http://szkolaprywatnaleszno.pl/userfiles/file/dopesofor.pdfIn PDF document text
    • http://europeanprofservices.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613357f0aa533---vemavuka.pdfIn PDF document text
    • https://www.crossfitparamaribo.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614860eebd406---27744202415.pdfIn PDF document text
    • http://avandcie-energy.com/ckfinder/userfiles/files/94817771152.pdfIn PDF document text
    • http://progettogeometra.it/userfiles/files/68934751357.pdfIn PDF document text
    • http://heryeryesil.com/resimlerfiles/68203162951.pdfIn PDF document text
    • http://lilit-realty.com/wp-content/plugins/super-forms/uploads/php/files/07m2o8akle42f8n4l1qvhko5v2/tusisej.pdfIn PDF document text
    • http://disonde.com/filespath/files/20211005064743.pdfIn PDF document text
    • http://df-foundry.net/d/files/sivadilixebamav.pdfIn PDF document text
    • http://www.brickchamber.com/ckfinder/userfiles/files/55329094113.pdfIn PDF document text
    • http://csc0898.com/userfiles/file/20210924090409_na25x1.pdfIn PDF document text
    • http://www.nisbd.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613fdf845b631---17917867542.pdfIn PDF document text
    • https://zniczekowalczyk.com/user_images/file/38133341783.pdfIn PDF document text
    • https://lotteppta.com/beta/assets/file/28073359283.pdfIn PDF document text
    • http://freeorden.com/media/file/28294646504.pdfIn PDF document text
    • https://www.verpoort-bouw.be/wp-content/plugins/formcraft/file-upload/server/content/files/16150a0b0d08dc---29704003792.pdfIn PDF document text
    • https://plasy.com/uploads/file/wokojove.pdfIn PDF document text
    • https://ashasuchikala.com/ckfinder/userfiles/files/lefobaripo.pdfIn PDF document text
    • https://lienlacanien.com/img_pages/file/38433182470.pdfIn PDF document text
    • https://braindevelopmentmaps.org/userfiles/files/8003251858.pdfIn PDF document text
    • https://adikketiga.com/contents/files/nagowelilopukakedagunoraj.pdfIn PDF document text
    • http://my-glc.com/uploads/file/fakuribakewuz.pdfIn PDF document text
    • http://www.garriagricola.com/wp-content/plugins/formcraft/file-upload/server/content/files/1615f507a85cc4---gubegoru.pdfIn PDF document text
    • https://watertorens.nl/userfiles/file/kobanebotevizodi.pdfIn PDF document text
    • http://feedproxy.google.com/~r/Xvkpad/~3/TxADE9PCSUw/uplcv?utm_term=how+to+get+free+robux+from+groupsPDF 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_off0000e4dc.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE4DC 20216 bytes
SHA-256: 2c4063b882f19b3e4069a6c9360af633c593d9784672fc12e786a442cdbeb012
font_01_sfnt_off00011946.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11946 10716 bytes
SHA-256: 980cbba6f135c8d34ef88721495d0dd36a2a3cc3c68bc0491c82cc96250ff480
font_02_sfnt_off000131ca.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x131CA 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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