Malicious PDF — malware analysis report

Static analysis result for SHA-256 5d86537b3bfaee6f…

MALICIOUS

PDF

75.0 KB Created: 2021-09-09 06:12:01 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: 88637bd84bf7f5588d93c801fdd6f7c0 SHA-1: a7e905d18bc3e5f132fac3df754e4597a394053c SHA-256: 5d86537b3bfaee6f230f9861e0a88b302d3ae1c55bf8843efedba5b8f31dbd1c
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file was detected as malicious by ML classifiers and ClamAV, indicating a high likelihood of malicious intent. It contains numerous embedded URLs, many pointing to PDF files on various domains, suggesting a link farm or redirection mechanism. The PDF_SEO_DISPOSABLE_LINK_FARM heuristic further supports this, indicating a tactic to obscure the true destination or distribute content across many domains. While no scripts were explicitly extracted, the nature of the heuristics and the numerous external links suggest the PDF is designed to redirect users to potentially harmful content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9973

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 http://akkoryazilim.com/userfiles/file/5999647066.pdf In PDF document text
    • https://casaalu.com/luutru/files/tivuwakukikeg.pdfIn PDF document text
    • https://alkathirilaw.com/userfiles/files/vexikelor.pdfIn PDF document text
    • http://inkjetartandimage.com/Uploads/file/33272778816.pdfIn PDF document text
    • http://tantusmarina.com/UserFiles/file/baxiniwufotosatemekejaj.pdfIn PDF document text
    • http://strandedtattoo.info/file/sixolusivabefod.pdfIn PDF document text
    • https://livre-art.com/ckfinder/userfiles/files/1395139820.pdfIn PDF document text
    • http://mbeautyconcept.com/upload/content_images/file/16680109088.pdfIn PDF document text
    • http://workontext.ru/media/file/lofewozefekumogak.pdfIn PDF document text
    • http://irina-beha.com/ckfinder/userfiles/files/kiloxurerenusetorugoben.pdfIn PDF document text
    • http://restavratorstvo.com/ckfinder/userfiles/files/neluxinidu.pdfIn PDF document text
    • https://ciiinnovationsummit.com/ci/userfiles/files/78617988486.pdfIn PDF document text
    • http://nikolabartakova.cz/files/file/80403287295.pdfIn PDF document text
    • https://dukupahit.com/contents/files/69674960392.pdfIn PDF document text
    • https://genia-groupe.fr/images/files/wefigelitefir.pdfIn PDF document text
    • http://terremeraude.com/userfiles/file/25027381345.pdfIn PDF document text
    • http://www.musicmaestrodiscos.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/161321b80eebe9---73937051970.pdfIn PDF document text
    • http://ilkyoukais.com/Images/Media/files/42335840739.pdfIn PDF document text
    • http://f-okinawa.com/img/tmp/file/lezivobomi.pdfIn PDF document text
    • http://tainanrup.longi.tw/uploadfiles/files/20210904_224522_8339.pdfIn PDF document text
    • https://poulinstrapscan.com/userfiles/file/wapewotubaladawinixazu.pdfIn PDF document text
    • http://nieruchomosciklodzko.pl/files/file/noxazuromuwuxena.pdfIn PDF document text
    • http://sinice-rasy.cz/files/file/salab.pdfIn PDF document text
    • https://nirmalujjwal.com/public/ckfinder/userfiles/files/28470739576.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/Om9ozkHLxGw/uplcv?utm_term=app+hider+for+android+apkPDF 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_off0000c14c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC14C 17720 bytes
SHA-256: 80a2d66c2d30d2bfd989c570e165df9cdf56f5cfe20cc9114ee3f3f3a6840393
font_01_sfnt_off0000eee6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEEE6 10356 bytes
SHA-256: a116c58ee39c741e717354f849ec0b96077b5ebd3f500dbf15add3ee4e65244b
font_02_sfnt_off00010633.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10633 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1