Malicious PDF — malware analysis report

Static analysis result for SHA-256 826a28435cdfd5d3…

MALICIOUS

PDF

72.0 KB Created: 2021-09-10 20:03:40 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: 018a9e5cfd5649af7d17479ecded083d SHA-1: 17eba8ab0beefc8302da4611ea6a175d58bcad4f SHA-256: 826a28435cdfd5d3ba94f8c2af08e84e13e9b8496c3290d2970d19a0b9cd88a3
126 Risk Score

Malware Insights

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

The PDF was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. It contains numerous embedded URLs, many pointing to PDF files hosted on various domains, suggesting a link farm or redirection mechanism. The heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' indicates a pattern of using disposable hosting for these links, likely to obscure the ultimate malicious destination.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9979

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://tele-video.ru/upload/files/gituvobopamikujifoxonom.pdf In PDF document text
    • https://massagetheory.ca/wp-content/plugins/super-forms/uploads/php/files/5fced69d5ad46126a10cffbdc442a73d/vopudagepit.pdfIn PDF document text
    • http://goldstecq.com/userfiles/file/55877383276.pdfIn PDF document text
    • https://monarchwinemerchants.com/wp-content/plugins/super-forms/uploads/php/files/70ba859fa0c7861caa1616ddffe599c8/lajaze.pdfIn PDF document text
    • https://www.adoz.cz/ckfinder/userfiles/files/fexivolejaxeve.pdfIn PDF document text
    • http://tg-focus.ru/userfiles/files/texanevafadupotoxax.pdfIn PDF document text
    • https://cortemadera.com/wysiwygfiles/file/zovabeves.pdfIn PDF document text
    • http://humanitool.ru/userfiles/file/rateregadaworixorimu.pdfIn PDF document text
    • http://sevvalturizm.com/rsm/files/gigadajadenitizonaro.pdfIn PDF document text
    • http://tuderprogettazione.it/userfiles/files/fonubegefeninifor.pdfIn PDF document text
    • https://homestayhoian.thamtuddt.com/uploads/image/files/22244679259.pdfIn PDF document text
    • https://frigosztufi.ro/ckfinder/userfiles/files/59941831740.pdfIn PDF document text
    • http://interroadholland.nl/userfiles/file/dibisimolizulivo.pdfIn PDF document text
    • http://ideatity.com/ckfinder/userfiles/files/86795898242.pdfIn PDF document text
    • https://prospr.fr/ckfinder/userfiles/files/15894945522.pdfIn PDF document text
    • http://ateliergermain.club/sites/default/files/file/91057515621.pdfIn PDF document text
    • https://fasleh.net/Files/files/65202522721.pdfIn PDF document text
    • https://tsegypt.com/file/45579272220.pdfIn PDF document text
    • http://timnhanhonline.com/upload/files/bedakobuliw.pdfIn PDF document text
    • https://huaku3c.tw/uploads/files/202109041559244696.pdfIn PDF document text
    • https://ruh-center.ru/userfiles/file/52836388565.pdfIn PDF document text
    • http://ahkkpcm.org/userfiles/vamuba.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/YTWXjIUwRh0/uplcv?utm_term=insta+story+ru+private+accountPDF 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_off0000b255.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB255 18372 bytes
SHA-256: bb1ceb3c772c1a85e955f6619578bd33a55571d158d2687a7672fe331c81c370
font_01_sfnt_off0000e1c2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE1C2 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000f9d9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF9D9 10552 bytes
SHA-256: 6f6cf4e80a9399696929abd307ae1459d875f1855b442934f6f5e00ace32e922

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