Malicious PDF — malware analysis report

Static analysis result for SHA-256 3f638be1a77b0a0f…

MALICIOUS

PDF

78.4 KB Created: 2021-07-18 11:57:04 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 5729f9b1290199339e7298ca4282911e SHA-1: 1975b7d125ad00f69ac9b9f1a65b55c4093515a1 SHA-256: 3f638be1a77b0a0f9246693aeaf22008666c6374b83169f9154b97926059abf4
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF contains numerous links to compromised WordPress sites, indicating it functions as a link farm. The ClamAV detection and ML classifier strongly suggest malicious intent, likely for phishing or malware delivery. No scripts were extracted, and the document body was unreadable, but the heuristic findings and URL analysis are sufficient to determine the attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9958

Heuristics 6

  • 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.
  • 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://nnk.gr/wp-content/plugins/formcraft/file-upload/server/content/files/160c70d3d86d6a---12609245758.pdf In PDF document text
    • http://bbfederico2.net/userfiles/file/80545652283.pdfIn PDF document text
    • https://jjmassociates.com/wp-content/plugins/super-forms/uploads/php/files/136eaa95fbdeaf58aa6d958f4ae5fe0f/76603407567.pdfIn PDF document text
    • http://pericosrentcar.com.mx/wp-content/plugins/formcraft/file-upload/server/content/files/160a0ac1db4565---97019398302.pdfIn PDF document text
    • https://encoregallery.us/wp-content/plugins/super-forms/uploads/php/files/67f1703c6480d40db4cc2a40bd9c558a/rukamak.pdfIn PDF document text
    • https://lakecountyoralsurgery.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607cec221480f---murimipipiwafekelidexosun.pdfIn PDF document text
    • https://baconbites.com/wp-content/plugins/super-forms/uploads/php/files/d8hmhkl4ar5ldpnj58j03s6sn1/lotup.pdfIn PDF document text
    • https://presstone.hu/userfiles/file/zofibag.pdfIn PDF document text
    • https://aquafilling.com/userfiles/file/rerewitazerifepogumison.pdfIn PDF document text
    • http://montaze.org/democms/userfiles/file/97631354012.pdfIn PDF document text
    • http://uyaviation.com/wp-content/plugins/formcraft/file-upload/server/content/files/160805d6c2e70f---54425236334.pdfIn PDF document text
    • https://janeunchained.com/wp-content/plugins/super-forms/uploads/php/files/h8rprsmt590q7hq6136u0lbiuh/28579482795.pdfIn PDF document text
    • https://alternativecarrepair.com/userfiles/file/11209944663.pdfIn PDF document text
    • https://www.landalastadservice.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608360800adb0---redevikabevubumevikojin.pdfIn PDF document text
    • https://www.xcelsus.de/wp-content/plugins/formcraft/file-upload/server/content/files/160a5b21a0c643---53675889712.pdfIn PDF document text
    • http://atek-ent.com/upload/file/10778835979.pdfIn PDF document text
    • http://angarakshaksecurity.com/userfiles/file/woxotaxev.pdfIn PDF document text
    • http://www.hcibatiment.fr/wp-content/plugins/formcraft/file-upload/server/content/files/160b06fe34b9f4---54586728074.pdfIn PDF document text
    • https://www.d-table.com/wp-content/plugins/super-forms/uploads/php/files/da17dac624fa31c9e3d5060042a3e209/38009961429.pdfIn PDF document text
    • https://extremetour74.ru/wp-content/plugins/super-forms/uploads/php/files/30916eb60b6b9072d10595f6ec4eab87/zolezonikibuzakuma.pdfIn PDF document text
    • http://indiebookoftheday.com/wp-content/plugins/formcraft/file-upload/server/content/files/16072ace87355d---63838307060.pdfIn PDF document text
    • https://avphunter.ro/ckfinder/userfiles/files/76862274267.pdfIn PDF document text
    • http://deurwater.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606e0d018725d---nisowikotokej.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/3vuEKuznOb8/uplcv?utm_term=microsoft+office+specialist+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_off0000d36f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD36F 10500 bytes
SHA-256: c42c80bc27e6ac197f8f2c654571ef89e6d8bcef13516e0312801bd1e486ab13
font_01_sfnt_off0000eb77.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEB77 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00010389.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10389 15912 bytes
SHA-256: fb85f3acc113659ef07873b3ce5a584eeb81b175ffb4b4984617f213efeddbeb

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