Malicious PDF — malware analysis report

Static analysis result for SHA-256 ef3dd0fb8f643848…

MALICIOUS

PDF

105.2 KB Created: 2021-08-03 23:41:37 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 6ef8f07819c347a97108abbb26608525 SHA-1: 6fdcb7780782e0657f24c48e5ad135fe270152af SHA-256: ef3dd0fb8f643848acb15a89836e3d4f68dcdd54152db34fbed4fb8c22b8c10d
156 Risk Score

Malware Insights

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

The PDF contains a link farm pointing to numerous other PDF files hosted on compromised WordPress sites, indicating a phishing or malware distribution attempt. The ML classifier and ClamAV detection strongly suggest malicious intent. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, lacking human-readable content to infer a specific lure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9970

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://sunarchegypt.com/userfiles/file/rokazekibibeza.pdf In PDF document text
    • https://fmpride.com/wp-content/plugins/super-forms/uploads/php/files/c29055996a6fb49365c326b76c78f820/28078545216.pdfIn PDF document text
    • http://infunplastic.com/d/files/65217993335.pdfIn PDF document text
    • https://alismobile.co.uk/wp-content/plugins/super-forms/uploads/php/files/7f250895c7762744842cd1c0631c0d18/111236092.pdfIn PDF document text
    • https://dnsbp.com/all4help/fckuserfiles/file/bewowolovetakizosupe.pdfIn PDF document text
    • https://monarchwinemerchants.com/wp-content/plugins/super-forms/uploads/php/files/3876e031a9988a120dc0fd4dce4b8cf7/mozesujezekijo.pdfIn PDF document text
    • https://xn----9sbccjdbca7cyaieg1a3j.xn--p1ai/wp-content/plugins/super-forms/uploads/php/files/0fb9aa799b19f751beafbe06002b5b6b/79919463866.pdfIn PDF document text
    • https://lochoanggia.com/upload/files/16457913276.pdfIn PDF document text
    • https://bettenbaehren.de/wp-content/plugins/formcraft/file-upload/server/content/files/16097bdc8a6442---vizobabe.pdfIn PDF document text
    • http://www.medical-psychology.gr/wp-content/plugins/formcraft/file-upload/server/content/files/16083332157186---68168671616.pdfIn PDF document text
    • http://vina2002.com/uploads/files/lapupo.pdfIn PDF document text
    • http://anma.pl/anma_edytor/file/koxivasitazudoxerifugut.pdfIn PDF document text
    • http://xinyaoqiye.com/upload_fck/file/2021-6-11/20210611115736586242.pdfIn PDF document text
    • https://www.sacproblemleri.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a1a3d9736ed---ronajurenem.pdfIn PDF document text
    • https://www.cibaospalaser.com/wp-content/plugins/super-forms/uploads/php/files/s51s4cg4fa2ccv5patic7jpuu6/83450434250.pdfIn PDF document text
    • https://inchiriereelicopterromania.ro/wp-content/plugins/formcraft/file-upload/server/content/files/1609c7bcb3d9a5---kiwojigul.pdfIn PDF document text
    • https://www.adcgrain.com/wp-content/plugins/super-forms/uploads/php/files/d96458b2a089284e1e5a689a14abb935/58614395622.pdfIn PDF document text
    • http://www.carolglassman.com/wp-content/plugins/formcraft/file-upload/server/content/files/160801e14a9509---dopakagazedomo.pdfIn PDF document text
    • http://redigonda.it/userfiles/files/84366622004.pdfIn PDF document text
    • http://acpiindia.com/userfiles/file/41400056084.pdfIn PDF document text
    • http://muabannhagiare.net/images/uploads/files/79336299335.pdfIn PDF document text
    • https://grandhotelbulgaria.com/userfiles/file/38289338105.pdfIn PDF document text
    • http://divorce-difficile.fr/userfiles/file/94160388263.pdfIn PDF document text
    • https://bindazzled.com.au/wp-content/plugins/super-forms/uploads/php/files/d0e21472942e65a41db69a22e42b48b6/gomizepuz.pdfIn PDF document text
    • https://kes-stv.ru/wp-content/plugins/super-forms/uploads/php/files/210f7a1135add5a14c6beda4e07dce03/kazinezilomejikez.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/GLLx1DTH0VQ/uplcv?utm_term=tempo+da+semanaPDF 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 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0001209f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1209F 16312 bytes
SHA-256: 7d15b2d6d265aaca51dda18faee70a1b8fa9d95ed54cb111fb0895789092f9ae
font_01_sfnt_off000136aa.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x136AA 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00014ec1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x14EC1 10180 bytes
SHA-256: ef701f225facf0b05fa0cd2017f534468ae7843aa611f7bae70e5b69bd843784
font_03_sfnt_off0001657f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1657F 19284 bytes
SHA-256: bfda1cfe3f96e85124e80ae0279b91c387e60fa071c22cb5cb12de417faa7369