Malicious PDF — malware analysis report

Static analysis result for SHA-256 77b4eaa5e20cebd7…

MALICIOUS

PDF

83.0 KB Created: 2021-09-03 17:36:44 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-07
MD5: 96fc1b572cfeeb887383dcbb511ae7d3 SHA-1: 4cebeb5ec53b9dc8a8c07f3bb93ec18baa92bad9 SHA-256: 77b4eaa5e20cebd7cd7786a5159f24ed4d49a92d6a4ee7d5528a37040fb31db7
156 Risk Score

Malware Insights

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

The PDF contains a large number of links, many pointing to compromised CMS upload directories, suggesting a link farm designed to distribute malicious content or phish users. The ML classifier and ClamAV detection strongly indicate malicious intent. While no scripts were explicitly extracted, the nature of the links and the PDF structure suggest potential exploitation or redirection to malicious JavaScript content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9991

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://duhochoangthanh.com/upload/files/kesorofedimu.pdf In PDF document text
    • https://www.zochrot.org/ckfinder/userfiles/files/kujaposiwiv.pdfIn PDF document text
    • https://steklo-shik.ru/userfiles/file/97319551545.pdfIn PDF document text
    • http://greece-ex.com/images/blog//file/79527477773.pdfIn PDF document text
    • https://organicfertilizerproduction.com/d/files/buvipujevivaduzogexifi.pdfIn PDF document text
    • http://www.insurancedirectcanada.ca/wp-content/plugins/formcraft/file-upload/server/content/files/160761535b27fa---joniwebebiwifuvizelo.pdfIn PDF document text
    • https://pabausa.org/wp-content/plugins/formcraft/file-upload/server/content/files/1608f754780e57---89624277811.pdfIn PDF document text
    • http://ivepe-elearning.gr/assets/UserFiles/mainHome/file/favikaz.pdfIn PDF document text
    • http://www.minaakshimajumdar.com/fckimages/file/90229243494.pdfIn PDF document text
    • https://cald-lighting.com/wp-content/plugins/super-forms/uploads/php/files/161ef74f50fa5e27e1d10ab6c48071cf/famasunapegozep.pdfIn PDF document text
    • http://paintingservicesonline.ca/wp-content/plugins/formcraft/file-upload/server/content/files/16074369089ace---pubukerawu.pdfIn PDF document text
    • https://champion-osk.pl/userfiles/file/69076146762.pdfIn PDF document text
    • https://www.toptalentusa.com/wp-content/plugins/formcraft/file-upload/server/content/files/160baaff77dc84---50504518522.pdfIn PDF document text
    • http://logo4you.dk/userfiles/file/sugolefusunifosofudux.pdfIn PDF document text
    • https://greenboo.vn/uploads/files/3093017402.pdfIn PDF document text
    • http://fullx.net/files/zuxotagoragutegodixum.pdfIn PDF document text
    • http://master-sign.ru/ckfinder/userfiles/files/87643698580.pdfIn PDF document text
    • https://nhachoxebus.com/upload/fck/file/vapafamufuzoruxozepagide.pdfIn PDF document text
    • http://jmlukanich.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/31330424300.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/GLLx1DTH0VQ/uplcv?utm_term=wd+elements+external+hard+drive+user+manualPDF 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_off0000e03b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE03B 10652 bytes
SHA-256: 984c084425b078eab8d1be5dfa1281c55449ab3b0673607e375c2527e21d5c8f
font_01_sfnt_off0000f868.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF868 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0001107a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1107A 17444 bytes
SHA-256: 787132c7c87131080200523d93d4abfd85b56d18a20f02f64962c8898f51a63d