Malicious PDF — malware analysis report

Static analysis result for SHA-256 57a42aeac3379e5d…

MALICIOUS

PDF

81.8 KB Created: 2021-09-08 17:59:12 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: 5c33b0da0c856e00c171cd2dbb0475f7 SHA-1: 9e3bf4f8f493a7a79f687d9f71d9e0e196117d82 SHA-256: 57a42aeac3379e5ddf5a7ef9161bff2bf02bf2e6f542ed47ea405ecbbd827bfc
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. The PDF contains numerous embedded URLs, many of which point to external PDF files, suggesting a link farm or redirection mechanism. The heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' further supports this, indicating the PDF is designed to host many links on disposable domains. No scripts were extracted, but the overall structure and URL distribution point towards a phishing or malware distribution campaign.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9911

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://fivetc.vn/uploads/files/99259788017.pdf In PDF document text
    • http://nakloboucku.cz/uploaded/file/saboguterejewewo.pdfIn PDF document text
    • http://lexprikson.com/admin/style/images/userfiles/file/93819733059.pdfIn PDF document text
    • http://imdmotors.com/uploadfile/file/2021090719091616.pdfIn PDF document text
    • http://flirtproducties.nl/ckfinder/userfiles/files/48324555041.pdfIn PDF document text
    • http://volker-issmer.de/userfiles/file/2021450294.pdfIn PDF document text
    • http://cargo3030.ru/wp-content/plugins/formcraft/file-upload/server/content/files/161388b154bc62---21864643328.pdfIn PDF document text
    • http://www.yoko-ono.be/images/userfiles/file/juparukixo.pdfIn PDF document text
    • http://longruiglass.com/ckfinder/userfiles/files/20210901_221746.pdfIn PDF document text
    • http://squash-fitness.cz/userfiles/file/zobufexilalodadedepa.pdfIn PDF document text
    • http://yuhao-tech.com/userfiles/file/bejijaxunuf.pdfIn PDF document text
    • http://nessium.net/userfiles/file/fudelemirufanok.pdfIn PDF document text
    • https://cli-kh.com/uploads/files/202109052210157963.pdfIn PDF document text
    • http://k-sta.kr/FileData/ckfinder/files/20210908_0081FCA667E298D9.pdfIn PDF document text
    • https://argumentua.com/i/file/29928948606.pdfIn PDF document text
    • http://antwerp-rentals.com/wp-content/plugins/formcraft/file-upload/server/content/files/16135020474fbc---73005953604.pdfIn PDF document text
    • https://oreopay57.com/ckfinder/userfiles/files/fodabarudarefivir.pdfIn PDF document text
    • https://isagrinio.gr/userfiles/xakenawosisifisonuxomoti.pdfIn PDF document text
    • https://thefertilizergranulator.com/d/files/bozapineladutexe.pdfIn PDF document text
    • http://daiwavn.com/uploads/image/files/vinenorafuwajefi.pdfIn PDF document text
    • http://acupunctuuryao.nl/ckfinder/userfiles/files/32986655637.pdfIn PDF document text
    • https://maintogelonline.bet/contents/files/31138218414.pdfIn PDF document text
    • http://yuanjiangchem.com/upload/files/90548280012.pdfIn PDF document text
    • http://www.wm-meyer.de/meyer/admin/editor/ckfinder/userfiles/files/22268487003.pdfIn PDF document text
    • https://network-italia.it/file/sodamitumukeweja.pdfIn PDF document text
    • http://myphammonly.com/luutru/files/rupebalawabidokos.pdfIn PDF document text
    • https://viboot.com/ckfinder/userfiles/files/857486682.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/1xuhb7AK25c/uplcv?utm_term=fundamentos+de+tribologia+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_off0000dac8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDAC8 17928 bytes
SHA-256: 5b480950ec15a4d115ef8fc5506ea0252eb081078c9faae4f9d2ed542bbff02e
font_01_sfnt_off000107b7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x107B7 11056 bytes
SHA-256: c0c0521d0bc9b2b9847af9ada86237086874f4a3772d41794c502398a3f52075
font_02_sfnt_off000120fc.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x120FC 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1