Malicious PDF — malware analysis report

Static analysis result for SHA-256 828785c02c397321…

MALICIOUS

PDF

82.6 KB Created: 2021-10-11 02:17:08 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-25
MD5: e3b916ec81732a9d255860eb6f8a3d3d SHA-1: c73dd4021d54092a21029a8328696c95fa933651 SHA-256: 828785c02c3973214267997d2c900f4991f0fa92a338625809712be38ccedb0a
156 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs, many of which point to compromised websites or disposable domains, indicating a link farm designed to redirect users. The ML classifier and ClamAV detection strongly suggest malicious intent, likely related to phishing or malware delivery. The presence of external URI heuristics and compromised CMS upload links further supports this assessment.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9964

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 http://ankurgroups.com/userfiles/file/3876116785.pdf In PDF document text
    • https://marcuspietrek.de/MARCUS/files/file/49963724686.pdfIn PDF document text
    • http://joyear.com/ckfinder/userfiles/files/4316353856.pdfIn PDF document text
    • http://dentish.ru/ckfinder/userfiles/files/85497336387.pdfIn PDF document text
    • https://congthuonghotel.vn/app/webroot/files/images/pages/files/mosimeji.pdfIn PDF document text
    • https://www.bluegreenshouseboats.in/wp-content/plugins/formcraft/file-upload/server/content/files/16160b57d91e3d---60412159729.pdfIn PDF document text
    • http://seibyou-koujien.com/files/files/wuviruxixe.pdfIn PDF document text
    • https://drinkpoint.com/uploads/files/wegub.pdfIn PDF document text
    • http://bagpack.com.np/wp-content/plugins/formcraft/file-upload/server/content/files/1615fcd9d43af8---85836358364.pdfIn PDF document text
    • https://concurs-euclid.ro/upload/fck/serodesevu.pdfIn PDF document text
    • http://eastcity.hu/ufiles/file/24828636791.pdfIn PDF document text
    • http://www.dfdtrading.sk/ckfinder/userfiles/files/vopojitufofiki.pdfIn PDF document text
    • http://dlugopis.kbo.pl/ckfinder/userfiles/files/faraforitizirosafijexixow.pdfIn PDF document text
    • http://spharma.ua/files/file/31741893758.pdfIn PDF document text
    • http://noithatachau.vn/webroot/img/files/kodafirarerofexubugobuzo.pdfIn PDF document text
    • https://academiesutherland.com/userfiles/file/majuruwovigibuso.pdfIn PDF document text
    • https://www.budgetskemaet.dk/wp-content/plugins/formcraft/file-upload/server/content/files/161538e422b86c---dikigax.pdfIn PDF document text
    • http://bright-mineral.com/uploadfile/file/2021091121531591.pdfIn PDF document text
    • http://gadkowski.pl/repository/filemanager/file/78832684074.pdfIn PDF document text
    • http://ageddfjtj.pretty-match.com/upload/files/44497282687.pdfIn PDF document text
    • http://panziofabian.hu/fck_kepek/9354207553.pdfIn PDF document text
    • https://giraffeng.net/infodaily/gen-ckfinder/userfiles/files/25428890919.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/fzgW7-mxBc0/uplcv?utm_term=photochemical+oxidation+of+hydrocarbons+and+nitrogen+oxides+results+intoPDF 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_off0000d43e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD43E 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000ec55.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEC55 11380 bytes
SHA-256: 75e5b0f74ffef88c943eb7dc2e0470c89bb6823620ef08433f574d1cec056aac
font_02_sfnt_off000106cc.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x106CC 20968 bytes
SHA-256: 4b53a5fb014ab13466985ea2a4737bbec97712b6203d2edf661c3cd71d0364b4