Malicious PDF — malware analysis report

Static analysis result for SHA-256 b8fd213939589526…

MALICIOUS

PDF

77.7 KB Created: 2021-09-22 12:21:39 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-31
MD5: f656d994a0e1561074cb658cba94b27b SHA-1: 8a6e24188fba8ab7bfd866c8c4d22b28bbf6d553 SHA-256: b8fd213939589526bfddb5c5c0c8eef49496551052ab8b651ca78840f08560bc
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a PDF file flagged by ML classifiers and ClamAV as malicious. It contains numerous embedded URLs pointing to external PDF files, suggesting a link farm or redirection mechanism. The PDF_SEO_DISPOSABLE_LINK_FARM heuristic indicates a pattern of using disposable hosting for these links, commonly seen in phishing or malware distribution campaigns. While no scripts were explicitly extracted, the presence of external links and the overall structure strongly suggest an intent to redirect the user to malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9992

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 http://hillsdalehorseboarding.com/ckfinder/userfiles/files/delugarexureruz.pdf In PDF document text
    • http://costanzolegal.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/22884229440.pdfIn PDF document text
    • https://ciar.vn/uploads/image/files/dolorajeruwawi.pdfIn PDF document text
    • http://ok-poland.com/userfiles/file/93962474046.pdfIn PDF document text
    • http://crisismobile.com/ckfinder/userfiles/files/dazolaxegido.pdfIn PDF document text
    • https://aporpeter.ro/userfiles/file/38976408355.pdfIn PDF document text
    • http://mamtaniketan.com/userfiles/file/54944346601.pdfIn PDF document text
    • https://10s317.com/uploads/files/202109020018245637.pdfIn PDF document text
    • http://philipp-haberland.de/images/upload/file/fejesipidagokojepuse.pdfIn PDF document text
    • https://www.cocochan.com.pk/wp-content/plugins/super-forms/uploads/php/files/5ee9d797af91a41370cfad353c91b4da/fijufutepoxakasu.pdfIn PDF document text
    • http://www.videobezopasnost.ru/ckfinder/userfiles/files/91222181435.pdfIn PDF document text
    • http://tajesink.com/Uploadfiles/files/davatogotopifiwaxolem.pdfIn PDF document text
    • http://importfoodfair.com/userfiles/image/2021/09/file/bojipozoge.pdfIn PDF document text
    • http://kpghomerepairs.com/uploads/image/files/sawigugusorik.pdfIn PDF document text
    • http://happyorderfood.com/uploads/files/82516763672.pdfIn PDF document text
    • http://plymouth-logs.co.uk/ckfinder/userfiles/files/84180955168.pdfIn PDF document text
    • http://saluteebenesseresas.it/userfiles/files/8033882001.pdfIn PDF document text
    • https://www.dyna-tech.nl/wp-content/plugins/formcraft/file-upload/server/content/files/1613bc83a2c397---54073746340.pdfIn PDF document text
    • http://krzeptowski.pl/file/72437021864.pdfIn PDF document text
    • http://yujinpharma.com/upload/files/48965218137.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/3vuEKuznOb8/uplcv?utm_term=imetric+mod+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_off0000cd7e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCD7E 17160 bytes
SHA-256: 24dc8ea1ca2a75f2f9bed238687a402c0c0ff786f56ec032a7b2c4ffede2ef21
font_01_sfnt_off0000f9fd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF9FD 10400 bytes
SHA-256: 9a6b9000128258fee7f2693a1a74915e751ca5cc7074325d7f822662470be203
font_02_sfnt_off00011188.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11188 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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