Malicious PDF — malware analysis report

Static analysis result for SHA-256 a77da5109d6a59d2…

MALICIOUS

PDF

120.2 KB Created: 2021-06-30 17:49:14 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-14
MD5: e635556192e13ed25beab43f939526e1 SHA-1: 8d633012f6485403682bdca18f7a5ac0a59637c0 SHA-256: a77da5109d6a59d282c9443067581bd15fcdf04c78df2bd0c92c39bdd1c29265
156 Risk Score

Malware Insights

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

The PDF file contains numerous embedded URLs, many of which point to compromised WordPress sites or disposable hosting, indicating a link farm designed to redirect users to malicious content. The ClamAV detection and ML classifier strongly suggest a phishing or trojan distribution intent. The document body is unreadable, but the heuristic firings and URL analysis are sufficient to determine the malicious nature.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9875

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 https://infrive.ru/uplcv?utm_term=touka+in+tokyo+ghoul+re PDF link annotation
    • http://uticahighclassof78.com/clients/8/89/89c70e22fe5ad1405280b455f64975d7/File/94604597973.pdfIn PDF document text
    • http://elonsummerstorage.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a6c9a54501d---11656945071.pdfIn PDF document text
    • https://www.physioaktivkramer.de/wp-content/plugins/formcraft/file-upload/server/content/files/160a574304535a---37564909188.pdfIn PDF document text
    • https://biocoils.com/img/file/wubarebazutew.pdfIn PDF document text
    • http://nghiencuuykhoa.com/uploads/userfiles/file/mepurapejerole.pdfIn PDF document text
    • https://freedomtampons.com/wp-content/plugins/super-forms/uploads/php/files/22da2178641bff8eeeac14adfa2b9168/soredugejer.pdfIn PDF document text
    • https://universitecentrale.net/uploads/FCK_files/file/27978730600.pdfIn PDF document text
    • http://ngpsusa.com/wp-content/plugins/super-forms/uploads/php/files/8ofd6vlgf67a2s5dp0q2vrgj6t/rumagetafenilenar.pdfIn PDF document text
    • https://www.ibyservice.com/wp-content/plugins/super-forms/uploads/php/files/079dcafc0bbbcf8ee73b66922df699a5/fafibenovewesajakemuniv.pdfIn PDF document text
    • https://advicezone.org.uk/wp-content/plugins/super-forms/uploads/php/files/08jgcrt372m4bq6k5acvqul729/jigudowu.pdfIn PDF document text
    • http://asu.com.vn/wp-content/plugins/super-forms/uploads/php/files/aiv6c5d6b9s7lmufg9l5f79t71/tulubuxogamazojuzabe.pdfIn PDF document text
    • http://argra.rs/wp-content/plugins/formcraft/file-upload/server/content/files/160c38fe77fcbd---jokagepagemubovegukuv.pdfIn PDF document text
    • https://www.bouwenaaneensterkwerkgeversmerk.nl/wp-content/plugins/formcraft/file-upload/server/content/files/1607f45e787d90---46070712826.pdfIn PDF document text
    • https://lashmakerpro.it/wp-content/plugins/super-forms/uploads/php/files/3jbles1n7u1b6hjjipbi1uog37/28789975007.pdfIn PDF document text
    • http://www.oschouston.com/osc/wp-content/plugins/formcraft/file-upload/server/content/files/1608cc5e1be341---tumuzivebop.pdfIn PDF document text
    • http://www.shipsupply.co.mz/wp-content/plugins/formcraft/file-upload/server/content/files/160a471b33389c---retel.pdfIn PDF document text
    • https://cr2tek.com/userfiles/Proj_Name//files/98656452311.pdfIn PDF document text
    • http://mudrkanuch.sk/editor_uploads/system/files/2412634308.pdfIn PDF document text
    • https://givemeit.ru/wp-content/plugins/super-forms/uploads/php/files/f526ff7bd3fc23d47a2f4383cf175b70/18141258975.pdfIn PDF document text
    • http://www.a-fairys-choice.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608d933b2c43d---notikapuge.pdfIn PDF document text
    • https://robertmatzuzi-massagetherapist.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/16086719c82700---lotumonutemel.pdfIn PDF document text
    • http://bascobrunswick.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/160833ad4b1b32---69518093021.pdfIn PDF document text
    • https://www.ayersworthglen.com/wp-content/plugins/formcraft/file-upload/server/content/files/160d9b7550870f---45080683503.pdfIn PDF document text
    • https://baconbites.com/wp-content/plugins/super-forms/uploads/php/files/2grbk8ockbb28sf9i1eq7bio74/33261087600.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 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off00011eb7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11EB7 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off000136c9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x136C9 19000 bytes
SHA-256: 31c7487ed8893e9cf90bd7f882a4361bd3d914570b007d76f779c7cab2e63609
font_02_sfnt_off00016693.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x16693 28824 bytes
SHA-256: f883f8e5855274aac05bf29593a04dcb962e5ef8b447edec24e187e75a7e7191
font_03_sfnt_off0001b9a0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1B9A0 10488 bytes
SHA-256: 79a73b3fd456737b4ef9f7c753f1529eb8dd6cb96c19d70b04265441af70e51f