Malicious PDF — malware analysis report

Static analysis result for SHA-256 8157423147660912…

MALICIOUS

PDF

81.4 KB Created: 2021-09-05 08:11:12 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-24
MD5: 8f2af86ccb36029b808cf75bd995e9dd SHA-1: 4a12bb1024eb3eef9f6b0be2bbd986c32d607fc5 SHA-256: 81574231476609123ee50cd602f8a01c241c0f9698dfcbeb2d0f079ac8aad9cd
156 Risk Score

Malware Insights

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

The PDF contains numerous external links, many pointing to compromised or disposable domains, indicating a link farm designed to lure users to malicious sites. The ML classifier and ClamAV detection strongly suggest malicious intent, likely for phishing or malware delivery. The document body is heavily obfuscated and unreadable, providing no direct content clues.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9981

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • PDF link farm points to compromised-WordPress upload storage medium PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM
    PDF contains multiple clickable links, across many distinct hosts, whose targets are random-slug files parked in the upload directories of vulnerable WordPress form plugins (FormCraft, Super Forms). This is the hallmark of the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains hosted on compromised sites. The PDF itself carries no exploit — the risk is the linked destinations.
  • 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://flexicourse.cz/res/file/gijogubojopaxapidawat.pdf In PDF document text
    • http://trevelsi.ru/ckfinder/userfiles/files/39232300210.pdfIn PDF document text
    • https://psihodesk.ro/ckfinder/userfiles/files/liworiwa.pdfIn PDF document text
    • https://resonanceacteurs.nl/userfiles/file/71159584209.pdfIn PDF document text
    • https://www.urban-quartz.co.uk/wp-content/plugins/super-forms/uploads/php/files/1b7f874bb602a09bfdb95848e5e034b0/tabafonevu.pdfIn PDF document text
    • http://sutphinsgermanshepherds.com/clients/21958/File/44351802429.pdfIn PDF document text
    • https://www.gs-gleichmann.de/wp-content/plugins/formcraft/file-upload/server/content/files/160a39fe59e566---34850682670.pdfIn PDF document text
    • https://autoandtruckrepair.net/nbloom/fckuploads/file/48455801368.pdfIn PDF document text
    • http://artgrafika.cz/userfiles/file/jevifuneduleval.pdfIn PDF document text
    • http://xn----7sbab1bcaqplb0ccyi9d.xn--p1ai/files/file/40409786369.pdfIn PDF document text
    • http://saiprogetti.net/userfiles/files/8977744320.pdfIn PDF document text
    • https://marikakozmetika.hu/editor_up/53453641621.pdfIn PDF document text
    • https://realwebguys.com/wp-content/plugins/formcraft/file-upload/server/content/files/16126e7ff53a83---53139202868.pdfIn PDF document text
    • http://akekaluck.com/ckfinder/userfiles/files/18581724903.pdfIn PDF document text
    • https://www.audifonosdoshoydos.com/wp-content/plugins/formcraft/file-upload/server/content/files/1612e96ede4b25---sewewa.pdfIn PDF document text
    • http://npi-management.org/ressource/site-image/files/12422885379.pdfIn PDF document text
    • https://www.golddustdental.com/wp-content/plugins/formcraft/file-upload/server/content/files/1610509c038fd8---59053417059.pdfIn PDF document text
    • https://promocionesnma.com/wp-content/plugins/super-forms/uploads/php/files/ca70f994c19808dedac8f0eaa6395f40/sibedakuwimiwumolupol.pdfIn PDF document text
    • https://bocion.com/ckfinder/userfiles/files/degijowasotinutivenufa.pdfIn PDF document text
    • http://tainghe.vn/userfiles/file/kitosavudimuduna.pdfIn PDF document text
    • http://fygl.net/uploads/file/210525408172.pdfIn PDF document text
    • http://feriaalainversa.com/uploaded/files/64776300154.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/YTWXjIUwRh0/uplcv?utm_term=antrenmanla+matematik+1+pdf+indirPDF 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_off0000d840.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD840 10496 bytes
SHA-256: 1515361df8369ba66eecb3b8aa85ab5e05eb5feefde9ae08ac8f1a0a63047a7c
font_01_sfnt_off0000f01c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF01C 18860 bytes
SHA-256: 2459c28061a80616fba6bb2c1caf9917f99e85e48ab42ea052845473b499dd35
font_02_sfnt_off00011e4d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11E4D 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1