Malicious PDF — malware analysis report

Static analysis result for SHA-256 a81b058faf70559b…

MALICIOUS

PDF

87.5 KB Created: 2021-09-06 01:54:06 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: bdc64a57d0b411b5e81375b252f5944b SHA-1: 54b0c950ff555f935ab37e892ce8dd42d11b94ab SHA-256: a81b058faf70559b2baa3e7c891ffd9bdf15efcb4eee6acb5b7bcc216415163c
156 Risk Score

Malware Insights

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

The PDF file was flagged as malicious by ML classifiers and ClamAV, indicating a high likelihood of malicious intent. It contains numerous embedded URLs that point to compromised CMS uploads and disposable hosting, suggesting a link farm designed for SEO poisoning or phishing. The document body is heavily obfuscated and unreadable, providing no direct content-based clues, but the heuristic findings strongly indicate a malicious redirection scheme.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9991

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://pistant.ru/uplcv?utm_term=toyota+lean+production+system+pdf PDF link annotation
    • http://latexindia.com/userfiles/file/90853411082.pdfIn PDF document text
    • http://studioindelicato.com/userfiles/files/doxuvawigibatenazaxuz.pdfIn PDF document text
    • http://smartmedicaleg.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608293e92f4f6---bejowojovem.pdfIn PDF document text
    • http://www.sevenchurchestour.net/seven/wp-content/plugins/formcraft/file-upload/server/content/files/1606c90987cee9---nevupe.pdfIn PDF document text
    • http://sb-78.ru/files/file/70905375178.pdfIn PDF document text
    • http://www.airportlimofortlauderdale.net/wp-content/plugins/formcraft/file-upload/server/content/files/1608508780a15d---1008146191.pdfIn PDF document text
    • https://kaemsp.org/upload/editor/file/50736184888.pdfIn PDF document text
    • http://brukbet.com/user_images/file/jobisebenatotogunizopunex.pdfIn PDF document text
    • https://oteaexpert.fr/cite_imgs/file/xexufusujaropizemumep.pdfIn PDF document text
    • http://www.itbaloch.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c3947a2d756---56251004411.pdfIn PDF document text
    • http://hoangnamjsc.com/upload/files/81458960823.pdfIn PDF document text
    • http://aaaexpressheating.com/userfiles/file/zuzomufagiwebemigobujunad.pdfIn PDF document text
    • https://mimpiindah168.com/contents/files/56311943763.pdfIn PDF document text
    • http://darienhigh69.com/clients/866565/File/44740327142.pdfIn PDF document text
    • https://home18.ru/wp-content/plugins/super-forms/uploads/php/files/ddde12f5c6407e7f62c3ab81a3cbe321/61085942246.pdfIn PDF document text
    • https://panificiopasticceriabattaglia.it/file/watubetazasekijoxo.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_off0000f008.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF008 18200 bytes
SHA-256: 97d2c9ed873b16139df08e33faa8123ff082904854230ed7943d9e61eb195824
font_01_sfnt_off00011fb9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11FB9 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off000137d0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x137D0 10956 bytes
SHA-256: 2b4fc3c4fa366625921fd001b346261ccce0c34257e2970e83948e9718755940

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