Malicious PDF — malware analysis report

Static analysis result for SHA-256 646c698742e7d7d8…

MALICIOUS

PDF

84.5 KB Created: 2021-09-19 05:49:28 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: b4c046c7473e339655412e900ac23e75 SHA-1: 503336959edf60fccf8f7280d9a959e8eaf593bf SHA-256: 646c698742e7d7d82786eba2d648509b01af18df7781b0dba92d0f34b65a8f58
156 Risk Score

Malware Insights

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

The sample is a PDF file flagged by ClamAV as Pdf.Phishing.Trojan and by an ML classifier as malicious. It contains numerous embedded URLs, many of which point to compromised WordPress upload storage or are part of a link farm on disposable hosting. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, suggesting it's not intended for direct user reading but rather to host links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9980

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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 https://fptica.ru/images/file/85507597065.pdf In PDF document text
    • https://mangalargalux.com.br/ckfinder/userfiles/files/rijutaxuxala.pdfIn PDF document text
    • http://naturalfurnish.com/userfiles/file/44947600141.pdfIn PDF document text
    • https://ispartaorganizasyon.com/ckfinder/upload/files/66964834502.pdfIn PDF document text
    • https://diversifiedhumansolutions.com/wp-content/plugins/super-forms/uploads/php/files/ebc8faee6f6f5980506161e6103f41e9/8238675254.pdfIn PDF document text
    • https://taksis.lv/taksis/userfiles/file/rixalenopek.pdfIn PDF document text
    • https://udachi.co.th/wp-content/plugins/super-forms/uploads/php/files/t98rhoktmpscmkqf4jutmfrm5u/puduzekiropal.pdfIn PDF document text
    • http://avalon-essenzen.at/userfiles/file/wofip.pdfIn PDF document text
    • https://chmelo.hu/sites/default/files/file/42424630381.pdfIn PDF document text
    • http://mudrkanuch.sk/editor_uploads/system/files/zexuwisobop.pdfIn PDF document text
    • http://asja-doll.ru/userfiles/file/74857500927.pdfIn PDF document text
    • http://jcnjl.com/userfiles/files/vonexemapigoz.pdfIn PDF document text
    • http://manilag.com/FileData/ckfinder/files/20210913_A68EDF5B52366E8E.pdfIn PDF document text
    • http://qiangka.com/ckfinder/userfiles/files/8115991880.pdfIn PDF document text
    • http://edu-soft.ru/site/htmlimages/file/vedevoliguvulalusoxano.pdfIn PDF document text
    • https://huaienclinic.com/uploadpic/files/798235279.pdfIn PDF document text
    • https://chokysitohang.com/Uploads/userfiles/files/34387342353.pdfIn PDF document text
    • http://eia-edu.com/userfiles/file/tosazajuziveluweso.pdfIn PDF document text
    • https://theshairpodcast.com/wp-content/plugins/super-forms/uploads/php/files/f597a7377dd2eeda93d981274ef9c15a/xazetoduxetelavobo.pdfIn PDF document text
    • https://cupanghitam.com/contents/files/raruloz.pdfIn PDF document text
    • http://tries.cz/media/images/upload/file/xokixuveduguz.pdfIn PDF document text
    • http://designgaleria.hu/userfiles/file/pasolobikopexajobugamin.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/3vuEKuznOb8/uplcv?utm_term=the+necklace+guy+de+maupassant+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_off0000e5f2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE5F2 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000fe04.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFE04 17516 bytes
SHA-256: 9e1e580a2ee07eecaf8a4b58d717a48ebe944434b040275561addf2d2fd155e1
font_02_sfnt_off00012af4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12AF4 11024 bytes
SHA-256: 8660507ad62a4ffed58a71f0215f93fd58c43c7add13b8b099551f327dd32511