Malicious PDF — malware analysis report

Static analysis result for SHA-256 823315e41b9452a2…

MALICIOUS

PDF

67.0 KB Created: 2021-10-04 08:54:21 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-25
MD5: 8131993ad332e1a5125239cd48f9898a SHA-1: e4f3ce44f77d201a4aba4daad4d2876b8cabbdc8 SHA-256: 823315e41b9452a2109a7efe77ede906d65d7a9acf520e33b9728f524c2ee2b1
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous embedded URLs, many pointing to compromised CMS upload directories or disposable hosting, indicating a link farm designed to redirect users. The ML classifier and ClamAV detection strongly suggest malicious intent, likely phishing or malware distribution. Although no scripts were explicitly extracted, the PDF structure and URL patterns are consistent with malicious document delivery mechanisms.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9993

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://ketchas.ru/uplcv?utm_term=learners+test+questions+and+answers+2021 PDF link annotation
    • https://pmcp-avac.com/files/upload-ckfinder/files/nobozogapuwor.pdfIn PDF document text
    • https://egyseg.eu/ckfinder/userfiles/files/mesigivobu.pdfIn PDF document text
    • http://tachikawa-derma.biz/ckfinder/userfiles/files/mitimonirukeranokuzitaz.pdfIn PDF document text
    • http://aroma-es.site/yamituki-n/uploads/files/pulidijaxagabawiseluk.pdfIn PDF document text
    • https://mobile-translator.eu/app/webroot/media/files/tikanilidido.pdfIn PDF document text
    • https://threadworx.com/thread/admin/uploads/file/80957495237.pdfIn PDF document text
    • https://anandalaya.in/resources/file/5590483722.pdfIn PDF document text
    • https://sk-developers.com/wp-content/plugins/formcraft/file-upload/server/content/files/16144451d8bc8f---foraxofaleso.pdfIn PDF document text
    • https://maidintown.co.uk/wp-content/plugins/super-forms/uploads/php/files/306fd8cec00cfa4c2f4c5fcb658fd32e/29060661655.pdfIn PDF document text
    • https://dongytueduc.com/wp-content/plugins/super-forms/uploads/php/files/qm57ldoeonsh5upql0oqm552t2/ziwew.pdfIn PDF document text
    • http://megalabsrl.it/userfiles/files/mowolimitesi.pdfIn PDF document text
    • http://antonioruizabogados.es/userfiles/file/80000997580.pdfIn PDF document text
    • https://blueparadise.pl/userfiles/file/44632735244.pdfIn PDF document text
    • https://behagi.eus/files/galeria/files/1849282984.pdfIn PDF document text
    • http://www.madiran-cruduparadis.fr/ckfinder/userfiles/files/wibomo.pdfIn PDF document text
    • https://flexi-cms.com/uploads/file/vawajuj.pdfIn PDF document text
    • http://suspensionestg.mx/userfiles/file/vedasesapazevojusozovo.pdfIn PDF document text
    • https://www.hkha.com.hk/ckfinder/userfiles/files/76258128253.pdfIn PDF document text
    • https://stmpallet.com/ckfinder/userfiles/files/6722503528.pdfIn PDF document text
    • 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_off0000a94b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xA94B 10780 bytes
SHA-256: ed87afbddfadc2afe46c5ed2a04152cbac4fe9c19e192e59e1fd7f63ef8ae7b5
font_01_sfnt_off0000c22f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC22F 14676 bytes
SHA-256: ae36cbcd1b64941c887668489b84a0653f585770561a00294f019a239cbe7be3
font_02_sfnt_off0000e6d5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE6D5 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1