Malicious PDF — malware analysis report

Static analysis result for SHA-256 ef865c9e0b404c0f…

MALICIOUS

PDF

72.0 KB Created: 2021-09-16 08:25:56 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 1f6e2bd05d051fa64344b436ffb89a17 SHA-1: 877ad1a9b8440241fb573a7ad21058bd150e3a14 SHA-256: ef865c9e0b404c0fb344d48dc2760ff5e604cf749878f434b0378bf5f327be2e
172 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

This PDF file contains embedded JavaScript, which is often used to exploit vulnerabilities or redirect users to malicious sites. The presence of multiple link farm heuristics and compromised CMS upload links indicates a deliberate attempt to host and distribute further malicious content. The ClamAV detection and ML classifier further support its malicious nature, likely serving as a downloader for a secondary payload.

Machine Learning

  • Nyx PDF Classifier malicious score 0.8252

Heuristics 8

  • 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.
  • 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.
  • Visual download / call-to-action button lure low SE_DOWNLOAD_BUTTON
    Document contains a call-to-action phrase ('Click here to download', 'Download Now', etc.) — low-signal unless other findings point to a malicious workflow
  • 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://mzr-avocats.com/buddha/ckfinder/userfiles/files/16667855315.pdf In PDF document text
    • http://sinoscaform.com/upload/ckimg/files/202109080909383901.pdfIn PDF document text
    • https://abicecream.ru/ckfinder/userfiles/files/24769775930.pdfIn PDF document text
    • http://letsfinal.com/userfiles/file/78142467453.pdfIn PDF document text
    • http://qdsenfeng.com/data/files/32772129569.pdfIn PDF document text
    • https://www.gml.de/wp-content/plugins/formcraft/file-upload/server/content/files/1613450a3b0795---suwosululudemodefu.pdfIn PDF document text
    • http://federicozucchettiarchitetto.eu/userfiles/files/79682051256.pdfIn PDF document text
    • https://nitm.ac.in/nitmeghalaya/ckfinder/userfiles/files/48803373808.pdfIn PDF document text
    • http://plovdivweek.com/app/templates/js/ckfinder/userfiles/files/77559460039.pdfIn PDF document text
    • http://iehyun.com/editorupload/file/13165112666.pdfIn PDF document text
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/1612f083d1c52e---sizovaboroxitanazera.pdfIn PDF document text
    • http://asalsold.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613d2869969a6---koduzesogarunadusixu.pdfIn PDF document text
    • https://editions-tlp.fr/ckfinder/userfiles/files/mujovuniwi.pdfIn PDF document text
    • https://wittnebel.dk/file/90033957620.pdfIn PDF document text
    • http://www.nagsa.es/ckfinder/userfiles/files/jivawilebifulu.pdfIn PDF document text
    • http://salamino.pl/userfiles/file/fikavajumakopabefemusu.pdfIn PDF document text
    • https://rajatotogroup3.com/contents/files/7475246985.pdfIn PDF document text
    • https://karpzbeldowa.pl/uploads/userfiles/files/jawani.pdfIn PDF document text
    • https://leosservices.com/userfiles/file/49570023473.pdfIn PDF document text
    • https://serpavenger.com/ckfinder/userfiles/files/piguzidunoxu.pdfIn PDF document text
    • https://www.digitalsofts.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613f4b974fbe5---3472609187.pdfIn PDF document text
    • https://parlagame.com/calisma2/files/uploads/10003810302.pdfIn PDF document text
    • http://cdenito.net/userfiles/file/95433552442.pdfIn PDF document text
    • https://anjingliar.com/contents/files/tujiserupuxenegowasakul.pdfIn PDF document text
    • http://modern-pro.ru/files/file/99425562929.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/LPIa9PGmDLg/uplcv?utm_term=route+nl+androidPDF link annotation
    • 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_off0000be48.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBE48 17600 bytes
SHA-256: 109027e089d471b8f7cf1fbca69bad2d3d4398be42bfd00fd2c06dc4655785fd
font_01_sfnt_off0000eb4a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEB4A 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00010361.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10361 10216 bytes
SHA-256: 1b20eaf8b8561617589aae7cf9f0f23acd25cf5006f7426208749d8bccaa0302

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