Malicious PDF — malware analysis report

Static analysis result for SHA-256 533a4c3f89cd1a86…

MALICIOUS

PDF

70.1 KB Created: 2021-09-17 03:04:45 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-07
MD5: de2c03f54d8e7f6280c8fb03896a8920 SHA-1: b3b99b5b8bdf06670618ccc9c5b664a2758d394f SHA-256: 533a4c3f89cd1a8694929414fd0454864884b076bc8b19840d1a51eecfed0ccc
126 Risk Score

Malware Insights

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

The PDF was flagged by a machine learning classifier and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, directing users to numerous disposable hosting sites, many of which are suspicious. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, suggesting it's not intended for human readability but rather to host links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9986

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://digitaldaya.com/imagenes/file/63489758258.pdf In PDF document text
    • http://invismortgagebroker.com/images/file/20657996401.pdfIn PDF document text
    • http://yung-shun.com/userfiles/file/gedikukozuzifanagulivif.pdfIn PDF document text
    • http://satakantaresort.com/user_img/files/48114812423.pdfIn PDF document text
    • http://srmtteaparty.com/uploads/files/202109151646481291.pdfIn PDF document text
    • http://motopujcovnateplice.cz/userfiles/file/46067534642.pdfIn PDF document text
    • https://valubil.com/public/uploads/cms_file/cms_files/jifowojupusarud.pdfIn PDF document text
    • http://hellnocancershow.com/wp-content/plugins/formcraft/file-upload/server/content/files/161348c7f33b26---96322683906.pdfIn PDF document text
    • http://mdtrend.hu/files/file/79501393989.pdfIn PDF document text
    • http://agrocare.hu/ckfinder/userfiles/files/78778977982.pdfIn PDF document text
    • http://vytvarnyobchod.cz/UserFiles/File/wipolomedigisujagafefari.pdfIn PDF document text
    • https://havilahbuilders.com/userfiles/file/kiwijavufakonameden.pdfIn PDF document text
    • http://quangcaovuanh.com/vietkiendo/upload/file/fukigifosanexikaxarun.pdfIn PDF document text
    • http://helderlive.nl/ckfinder/userfiles/files/13945510336.pdfIn PDF document text
    • https://aitalk.vn/upload/files/90985278484.pdfIn PDF document text
    • http://chip-chup.hu/upload/file/76085935092.pdfIn PDF document text
    • http://furniture83.com/upload/files/fivutuwotugoruxe.pdfIn PDF document text
    • https://khonggiansachhanoi.vn/uploads/files/85031728323.pdfIn PDF document text
    • http://cualuoiskydoor.com/webroot/img/files/72368293956.pdfIn PDF document text
    • https://www.wsbe17hongkong.hk/_bin/ckfinder/userfiles/files/vumugizadujewekiwezodij.pdfIn PDF document text
    • https://indirimlipin.com/calisma2/files/uploads/61028669393.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/3CAf4wW3hvY/uplcv?utm_term=praying+mantis+kung+fu+pdfPDF 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_off0000b159.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB159 16196 bytes
SHA-256: c6f4cf3635d8485aa9721f45b347088e0e47be622f5fa7f5415e41a87b45e709
font_01_sfnt_off0000d9db.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD9DB 10848 bytes
SHA-256: 0087cfaad9b01a3b0aca7543e16360e14d290e3cbaa816da0b3487b5a96dd173
font_02_sfnt_off0000f2ad.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF2AD 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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