Malicious PDF — malware analysis report

Static analysis result for SHA-256 81310c596683f41c…

MALICIOUS

PDF

84.0 KB Created: 2021-09-06 14:05:13 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: 5320b312d3fa7e65900d0713e1175224 SHA-1: d73b42d407881829ecc8a61f75a6e9d6820d4193 SHA-256: 81310c596683f41c2614c80dc46584c648037e4196e02d1a7e3e98c8ffdfda8e
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF contains numerous embedded URLs, many of which point to compromised CMS uploads 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 delivery through these links. No scripts were extracted, but the structure and URL analysis are sufficient to infer a malicious purpose.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9877

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://strandedtattoo.com/file/teretubazubitex.pdf In PDF document text
    • https://www.bouwenaaneensterkwerkgeversmerk.nl/wp-content/plugins/formcraft/file-upload/server/content/files/1612ea3f3abd5b---vegobixezifegotebilemiloz.pdfIn PDF document text
    • https://mbzl-pro.xyz/web/img/podborky/files/93624315819.pdfIn PDF document text
    • http://farashimirooz.com/files/datubaf.pdfIn PDF document text
    • http://mywymc.com/userfiles/file/51208570069.pdfIn PDF document text
    • http://cgt-fo-csc.fr/wp-content/plugins/formcraft/file-upload/server/content/files/160804c050c76a---92570099173.pdfIn PDF document text
    • http://cuacuonnhanh.vn/Images_upload/files/wunifilivez.pdfIn PDF document text
    • http://www.multigacos.com/admin/uploaded/fck/file/vadikiluxunolajubojate.pdfIn PDF document text
    • https://holocaustresearch.pl/nowy/photo/file/56503182608.pdfIn PDF document text
    • http://coomargroup.com/ckfinder/userfiles/files/teratazenotizixuluxu.pdfIn PDF document text
    • http://sklepjola.pl/userfiles/file/vanar.pdfIn PDF document text
    • https://comtraining.cl/userfiles/files/65116903936.pdfIn PDF document text
    • http://cavusofis.com/images_upload/files/67557073036.pdfIn PDF document text
    • https://414movement.com/wp-content/plugins/super-forms/uploads/php/files/7ce1f91a59ac635bda6435eb6af2ca9d/jobubamar.pdfIn PDF document text
    • http://qiuyutv.com/userfiles/files/20210812023233.pdfIn PDF document text
    • https://limpjet.com.br/wp-content/plugins/super-forms/uploads/php/files/7cc11d492deda69eef8e09acb7dea5fc/8929596019.pdfIn PDF document text
    • http://instandee.com/Images_upload/files/3250407759.pdfIn PDF document text
    • http://aqcons.vn/upload/files/95851991673.pdfIn PDF document text
    • http://liburnia.pl/userfiles/file/33708281513.pdfIn PDF document text
    • http://bubb.cn/up_file/file/mabajaleredebepezotalakog.pdfIn PDF document text
    • http://rszm88.com/upfolder/e/files/20210620210124.pdfIn PDF document text
    • https://pametnidom.hr/pametne_kuce/userfiles/file/95605323832.pdfIn PDF document text
    • http://www.icodar.com/wp-content/plugins/formcraft/file-upload/server/content/files/16070119e7607b---pagogejazumisawazo.pdfIn PDF document text
    • http://www.hcibatiment.fr/wp-content/plugins/formcraft/file-upload/server/content/files/160792fca0f325---joposogivupafawinuwug.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/1xuhb7AK25c/uplcv?utm_term=mpsc+rajyaseva+syllabus+in+marathi+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 5

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000c0e4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC0E4 19020 bytes
SHA-256: b1f0393f4f04a7ee161b189c59293e69abefc297dec2c2ba4ad570bb96ce79ea
font_01_sfnt_off0000f14e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF14E 16192 bytes
SHA-256: 126aabc53b187bc4421529373f04e2f66a11804dfeaeb35cb650b132d56c1dbd
font_02_sfnt_off000106ef.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x106EF 1680 bytes
SHA-256: 6c08887b596ecb472c5a0482df8c2f828d83fc5b5d16111ed0caa1fced1b35dc
font_03_sfnt_off00010eec.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10EEC 11308 bytes
SHA-256: b73ac95f9bd31a5d3786102b18d8de55a4007ad635b19c42d3b81f703649a599
font_04_sfnt_off00012911.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12911 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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