Malicious PDF — malware analysis report

Static analysis result for SHA-256 41335f9fecc3d0bf…

MALICIOUS

PDF

72.8 KB Created: 2021-09-19 21:28:52 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: 0b4c84693e8d5a5723087d1f9a0ff648 SHA-1: 438eb27aa5f447b099623560e7e1e71d3e111c01 SHA-256: 41335f9fecc3d0bf50aef9597ffd159d54cec403708f4dc379d2a1b8deed60fa
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample was detected as malicious by ML classifiers and ClamAV, indicating a high likelihood of malicious intent. The PDF contains numerous embedded URLs pointing to various domains, suggesting it functions as a link farm or redirection mechanism. The heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' strongly supports this, indicating the PDF is designed to host many links on disposable hosting. No scripts were extracted, but the presence of numerous external URIs suggests the primary attack pattern is to redirect users to potentially malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9976

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://cructi.ru/uplcv?utm_term=chatbot+using+android+studio PDF link annotation
    • http://eska-lift.ru/userfiles/file/lazisujoku.pdfIn PDF document text
    • http://budropol.de/Upload/file/62579290785.pdfIn PDF document text
    • http://fuhua.tumujike.com/assets/upload/files/202109121812326138.pdfIn PDF document text
    • https://kohphanganhotelandtour.com/userfiles/file/vigabinad.pdfIn PDF document text
    • http://qboardapp.com/wp-content/plugins/super-forms/uploads/php/files/1b9053a6b3ab238950517c6ee42fc38b/nivuropowozok.pdfIn PDF document text
    • http://josquin-capella.de/download/4519134259.pdfIn PDF document text
    • http://brain-sh.tw/upload/file/nujexar.pdfIn PDF document text
    • http://lexxyin.net/files/fckeditor/file/57997049820.pdfIn PDF document text
    • https://arvikabc.com/images/uploadedimages/file/minemovusemutamawevupawug.pdfIn PDF document text
    • https://tekdalyapi.com/upload/ckfinder/files/67773306270.pdfIn PDF document text
    • http://tlumacz-lipno.pl/pdrzewiecki/files/97867073832.pdfIn PDF document text
    • http://bscartridge.com/pic/24562564705.pdfIn PDF document text
    • http://gaudi.tw/upload/file/nuzurapotapitoravomi.pdfIn PDF document text
    • https://www.fyna.com.au/application/third_party/ckfinder/userfiles/files/1408019580.pdfIn PDF document text
    • https://balajitutorial.com/admin/userfiles/file/daxekudegon.pdfIn PDF document text
    • http://oguzlarotomatiksanziman.com/depo/sayfaresim/file/47298972351.pdfIn PDF document text
    • http://ukkies.be/userfiles/file/lekuxefuwum.pdfIn PDF document text
    • http://abwingsjanaf.com/uploads/files/73471899541.pdfIn PDF document text
    • http://koreaticketland.com/userfile/file/zimeku.pdfIn PDF document text
    • http://farashimirooz.com/files/52142540439.pdfIn PDF document text
    • https://nuteuit.ro/ckfinder/userfiles/files/konuxo.pdfIn PDF document text
    • https://demo-calson.garment-pro.com/ckfinder/userfiles/files/76302752474.pdfIn PDF document text
    • https://tssch.in/tssch/application/admin/uploads/file/62181874581.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_off0000ba71.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBA71 16756 bytes
SHA-256: f11db3a3611962837b675c4f80ed13969fe974fcc22ef3a13fe72f22ebdd5f3f
font_01_sfnt_off0000e599.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE599 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000fdb0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFDB0 10620 bytes
SHA-256: b82e0334aa81bd4c653f9f1ef00e5ebb6949a31f95b348664d3b1bdeeae69b01

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