Malicious PDF — malware analysis report

Static analysis result for SHA-256 681517b6fd8e4202…

MALICIOUS

PDF

82.6 KB Created: 2021-10-07 01:11:39 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-23
MD5: 262c624d3fa368497c5228131d7f730f SHA-1: 17721d27bd8bb0e8544a97b564de27c9d443d1bd SHA-256: 681517b6fd8e420283f65388bc4374b45717a19b4cfe0bb6a5a6f187ae860db7
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a PDF file flagged by ClamAV as Pdf.Phishing.Trojan and by an ML classifier as malicious. It contains embedded JavaScript and a large number of external URLs, many of which point to compromised CMS uploads or disposable hosting, suggesting a link farm designed to distribute malicious content or redirect users to phishing sites. The presence of embedded JavaScript indicates an attempt to execute code within the PDF viewer.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9960

Heuristics 7

  • 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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://crewmak.ru/uplcv?utm_term=solenoid+equation+magnetic+field PDF link annotation
    • http://cellesekorea.com/ckupload/files/97494829393.pdfIn PDF document text
    • http://lagostena.it/userfiles/files/gutamitaniw.pdfIn PDF document text
    • http://clickvay.com/upload/files/pakebifad.pdfIn PDF document text
    • https://husvagnsexpo.se/wp-content/plugins/formcraft/file-upload/server/content/files/161383ae93958b---vapimuvokiseka.pdfIn PDF document text
    • http://wsmr.us/userfiles/file/pezewu.pdfIn PDF document text
    • https://tumujerrusa.com/userfiles/45050669734.pdfIn PDF document text
    • http://arenabilardo.com/data/_files/donipuxip.pdfIn PDF document text
    • http://crisismobile.com/ckfinder/userfiles/files/wawevimuno.pdfIn PDF document text
    • http://kartinatv.org/uploads/files/89914843312.pdfIn PDF document text
    • https://mosoptagro.ru/wp-content/plugins/super-forms/uploads/php/files/d4c2302b3d97baa62f96e3b1ef51801d/fapenoziwezokatiturir.pdfIn PDF document text
    • http://www.thegrcinstitute.org/app/webroot/js/ckfinder/userfiles/files/guraga.pdfIn PDF document text
    • https://dunaweb.co/bg_image/files/pemoweni.pdfIn PDF document text
    • https://marblobaths.com/app/webroot/img/files/79045133119.pdfIn PDF document text
    • http://jsqnchem.com/upload/files/kikav.pdfIn PDF document text
    • https://www.hotelrestaurantmacarena.fr/ckfinder/userfiles/files/14952478211.pdfIn PDF document text
    • http://www.appsolutely.sg/wp-content/plugins/formcraft/file-upload/server/content/files/161519f7fc4ed8---dasuzinedudenudob.pdfIn PDF document text
    • http://vdi.vn/userfiles/file/gopatigofusekabedolubo.pdfIn PDF document text
    • http://kliknetezde.cz/admin/obrazky/file/mogigorokugif.pdfIn PDF document text
    • https://arnetbilgisayar.com/upload/ckfinder/files/44783131216.pdfIn PDF document text
    • https://cortopolis.ar/userfiles/file/ronewadijezimuvalaxufimet.pdfIn PDF document text
    • http://clairvoyantinfotech.com/demo/images/49510503043.pdfIn PDF document text
    • http://www.gieskestukadoors.nl/ckfinder/files/files/50299104276.pdfIn PDF document text
    • https://0a3exp.com/upfiles/editor/files/vusefo.pdfIn PDF document text
    • 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_off0000db42.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDB42 18984 bytes
SHA-256: c4d6eb74f5dc6359d92775571a25c3532198cbc00f417d6546a99833160bce0c
font_01_sfnt_off00010c34.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10C34 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0001244b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1244B 10872 bytes
SHA-256: 7a9b4386f39396eaf9c7f98c91b7fd5de1bccb435dbef3055aaa4b3d87724466