Malicious PDF — malware analysis report

Static analysis result for SHA-256 cb17056a4bbb5e3d…

MALICIOUS

PDF

88.2 KB Created: 2021-09-22 11:08:47 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: df8a134de57c7ec222cd7eb360b5e5a0 SHA-1: 8dcc97f54dc43ba52b06ad07fcf1799729c7dc67 SHA-256: cb17056a4bbb5e3dcef2714e72471afbdcff21912884ac3f0cc205ebbe977a1d
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file was flagged as malicious by ML classifiers and ClamAV, indicating a high likelihood of malicious intent. It contains numerous links, many pointing to compromised CMS upload storage or disposable hosting, suggesting a link farm designed to redirect users to malicious sites. While no scripts were directly extracted, the PDF structure and link farm heuristics strongly suggest an attempt to deliver a phishing or malware payload via these external URLs.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9973

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 https://karolinanowak.com/userfiles/file/wuzojeb.pdf In PDF document text
    • http://thietbiotovn.com/Images_upload/files/67826343998.pdfIn PDF document text
    • http://usmleworkout.com/files/file/4160673191.pdfIn PDF document text
    • https://lorenzonimmigrationlaw.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613c05b29cd38---26851101140.pdfIn PDF document text
    • http://gysanya.com/upload/file/210920001622014347o8avsd3u40oa.pdfIn PDF document text
    • https://hirurgija.me/files/fuvikowati.pdfIn PDF document text
    • https://ehotelgateway.com/bot/ckfinder/uf/files/vemujodivasufazevufeza.pdfIn PDF document text
    • https://sellos-mecanicos.com/wp-content/plugins/super-forms/uploads/php/files/5202018f50ed640fb2c2a5b26a3e700b/61339906649.pdfIn PDF document text
    • https://xn-----6kcabagcgfjsxjciriy6alkh6a7aqk.xn--p1ai/wp-content/plugins/super-forms/uploads/php/files/bec5f4aa0f06f85f5e414dd3663d15ab/jirupuwidaxoge.pdfIn PDF document text
    • http://robbes.nl/media/files/rugurafubaniju.pdfIn PDF document text
    • https://jkmart.net/FCKFiles/File/sabiropivali.pdfIn PDF document text
    • http://wawa757.com/uploads/files/81108357461.pdfIn PDF document text
    • http://ingatlantv.tv/userfiles/files/gekaxejok.pdfIn PDF document text
    • http://bajajsports.com/userfiles/file/7187067726.pdfIn PDF document text
    • https://ingatlanfelugyelet.hu/uploads/file/mazajewarovivasaw.pdfIn PDF document text
    • http://bhk-aindling.de/userfiles/files/moxaruridafuzib.pdfIn PDF document text
    • https://ciar.vn/uploads/image/files/98232018904.pdfIn PDF document text
    • http://nensi.si/upload/file/jorekifago.pdfIn PDF document text
    • https://molecult.metallo-tests.ch/sites/web/upload/files/31562376817.pdfIn PDF document text
    • http://mikomisushiwc.com/uploads/files/32364323647.pdfIn PDF document text
    • http://nyett.hk/uploads/news/files/96449310049.pdfIn PDF document text
    • https://kicksomeglass.com/wp-content/plugins/super-forms/uploads/php/files/db3b562b7e66020677ed99762c38bc37/pililizukulenamofipe.pdfIn PDF document text
    • http://gleb777.com/fck_upload/file/ludid.pdfIn PDF document text
    • https://harpethvalleypto.org/wp-content/plugins/super-forms/uploads/php/files/06169c4064b11a94ad63c5f3d391d0cb/bodevefepaburitijinegive.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/3vuEKuznOb8/uplcv?utm_term=how+to+create+table+in+sqlite+androidPDF 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_off0000ef16.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEF16 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0001072d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1072D 10724 bytes
SHA-256: a06ae9c085d3bbcd86980951f5050a9b4461707ee6032d4676eecc213d010520
font_02_sfnt_off00011fb1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11FB1 19376 bytes
SHA-256: b467e7934de1f3593eba6c7010e175410d0c90e892e27884c097706296e7eb74