Malicious PDF — malware analysis report

Static analysis result for SHA-256 f4bf9e4b31b43048…

MALICIOUS

PDF

75.4 KB Created: 2021-09-09 05:21:22 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: d50fa03bc9c3cb3c556fe92ec69a5e72 SHA-1: d110ef604832d5094394d743ccb8ed8038b16018 SHA-256: f4bf9e4b31b430488db44e323c6f65be5c1c6b19356f7c43d83a9cb9c13e1a8f
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. It contains numerous embedded URLs, many of which point to external PDF files hosted on potentially disposable 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 sites. No scripts were extracted, but the presence of external links and the overall detection suggest the PDF's purpose is to redirect users to malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9976

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://speckrepeg.by/UserFiles/files/85539057144.pdf
    • http://www.dawnrotaryclub.tw/UserFiles/files/40375237948.pdf
    • http://j1medical.com/uploaded/file/42161295211.pdf
    • http://dymenahealthcare.com/upload/fckeditor/file/pozofizegafizilowetevos.pdf
    • http://ipvoicenj.com/wp-content/plugins/formcraft/file-upload/server/content/files/161374c1bd7485---30845611723.pdf
    • http://sprinter-lab.ru/content/File/janigafegajadu.pdf
    • https://tkpmission.org/wp-content/plugins/formcraft/file-upload/server/content/files/161304c78dc6d8---48051438858.pdf
    • http://sjhrz.com/images/upload/File/32607206338.pdf
    • http://stellarp.com/userfiles/file/fufeli.pdf
    • http://laserinnsbruck.com/static/26972256833.pdf
    • http://parateam.cz/file/duzuliresegifomijul.pdf
    • http://xn----8sbemnkjd7bfu.xn--p1ai/design/img/upload/file/13862636612.pdf
    • https://jin-ji.com/upload/files/futaparirisobozif.pdf
    • https://marathonlaval.com/userfiles/files/vemigopud.pdf
    • http://tubemakingmachine.com/uploadfile/files/mopegiw.pdf
    • http://allamericannursing.com/userfiles/file/wisosofimokujutamesikan.pdf
    • https://brune-schmuckwerk.de/ckfinder/userfiles/files/detafit.pdf
    • http://ventilyatsia-v-sochi.ru/ckfinder/userfiles/files/kigeweguxitulutike.pdf
    • http://yachtales.net/admin/userfiles/files/57465392310.pdf
    • http://arabic.cz/ckfinder/userfiles/files/fokorafamavamex.pdf
    • https://e-tta.com/app/webroot/userfiles/files/16707193045.pdf
    • http://swiss-ex.com/images/blog/file/wotukejenevo.pdf
    • https://thaibamboorestaurant.ca/phpsites/bard_ford/uploads/file/26213895723.pdf
    • https://feedproxy.google.com/~r/Uplcv/~3/A3Ryygt5BCM/uplcv?utm_term=ben+10+ultimate+alien+game+apk
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000bb03.bin
500ac59250076ad58ce75b40c73596ea601d3523de4181f6b376bb51cc6c715e		 pdf-font-stream PDF embedded font (sfnt) at offset 0xBB03 10628 bytes
font_01_sfnt_off0000d356.bin
747cb43e7c4fdf280beef94276235c4ccc51c0f198e7fa47c504ead1b3911618		 pdf-font-stream PDF embedded font (sfnt) at offset 0xD356 20216 bytes
font_02_sfnt_off00010805.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1		 pdf-font-stream PDF embedded font (sfnt) at offset 0x10805 16792 bytes

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