Malicious PDF — malware analysis report

Static analysis result for SHA-256 f9e23b09df6e141e…

MALICIOUS

PDF

90.7 KB Created: 2021-10-24 20:09:34 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-24
MD5: 07f9ed5b91199bbb42fd861a771ab870 SHA-1: 5817a4ce36e12d8af1c74956077011a3693ea2d0 SHA-256: f9e23b09df6e141e8a679af39de6c9d5b7344e7419c5046c029d77cc005fdab4
126 Risk Score

Malware Insights

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

The sample is a PDF file flagged by ML classifiers and ClamAV as malicious. It contains numerous embedded URLs, many pointing to PDF files on various domains, indicating a link farm or distribution network. The heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' strongly suggests this is the primary function, likely to manipulate search engine results or serve as a landing page for further malicious activity.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

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://goksirkrupskimlyn.pl/img/upload/files/57270284975.pdf In PDF document text
    • http://pokwuttibut.com/file_media/file_image/file/gogotasesorefemiguxuka.pdfIn PDF document text
    • https://073741256.com/uploads/files/202109061150302355.pdfIn PDF document text
    • https://relans-nn.ru/images/docs/file/21804978789.pdfIn PDF document text
    • https://minhvuongthuphap.com/upload/ck/files/xuleronel.pdfIn PDF document text
    • http://primebrokeragetx.com/ckfinder/userfiles/files/lenodu.pdfIn PDF document text
    • http://autovoda.ru/upload/files/jolapar.pdfIn PDF document text
    • http://dtyxbpzx.com/filespath/files/20210913204450.pdfIn PDF document text
    • http://www.awakohchang.com/image/upload/File/2414867072.pdfIn PDF document text
    • http://winhazel.com/indigo/ckfinder/userfiles/files/lilejidaga.pdfIn PDF document text
    • http://ambvet-trefontane.eu/userfiles/files/xikomit.pdfIn PDF document text
    • http://mhinflatable.com/upload/file/16715500149.pdfIn PDF document text
    • http://soskuwait.com/outscapes/admin/ckeditor/uploads/ck/files/lakekada.pdfIn PDF document text
    • https://imaggu.com/ci/userfiles/files/3125994791.pdfIn PDF document text
    • http://www.mousumibanerjee.com/fckimages/file/womalara.pdfIn PDF document text
    • http://ajisushionline.com/uploads/files/52756949302.pdfIn PDF document text
    • http://yacpa.org/yacpafiles/file/86749980902.pdfIn PDF document text
    • http://bakefruit.com/uploads/files/202110032106576386.pdfIn PDF document text
    • http://mavachhaiphong.com/upload/files/vunupikevigol.pdfIn PDF document text
    • http://www.ufolep-69.com/contenus/files/7785849225.pdfIn PDF document text
    • http://chiangmaicharmingtravel.com/ckfinder/userfiles/files/tuxuzigodowixufaninuvuz.pdfIn PDF document text
    • http://www.theagentpipeline.com/wp-content/plugins/formcraft/file-upload/server/content/files/16171556c519cb---demabowetevujosax.pdfIn PDF document text
    • https://computerzone.pk/file/ziwaditesi.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Gsjc/~3/oscUj7J0Gjw/uplcv?utm_term=growing+statice+from+seedPDF 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_off0000f6b1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF6B1 20340 bytes
SHA-256: 1713cbf57d4e94a71c9e82844f62457f87dbd418c06bac67281122e7da969477
font_01_sfnt_off00012bdd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12BDD 10896 bytes
SHA-256: 93f96316f588799c0fecb5ed815ee78c7979e693a40de60df6a14519730e5c53
font_02_sfnt_off000144fb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x144FB 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1