Malicious PDF — malware analysis report

Static analysis result for SHA-256 138cbd214162bb7c…

MALICIOUS

PDF

83.9 KB Created: 2021-08-05 03:24:03 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-17
MD5: e26784b00ff15d318416d768bb0f07fe SHA-1: 0e184d5b529c7e0a178cd8180130c9552599b149 SHA-256: 138cbd214162bb7c07956051bb40205f3c9e71a047140b11f0a138d4aee9c848
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

This PDF file was flagged by multiple heuristics as malicious, including a critical ClamAV detection and an ML classifier indicating a high probability of maliciousness. The heuristics indicate the PDF functions as a link farm, directing users to numerous external URLs, many hosted on compromised CMS platforms or disposable domains. The presence of embedded URLs and the nature of the link farm suggest an attempt to direct users to phishing sites or download further malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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://philabc.ru/uplcv?utm_term=sheep+brain+dissection+lab+answers PDF link annotation
    • http://allgeology.ru/ckfinder/userfiles/files/walinetuzi.pdfIn PDF document text
    • http://remontnoedelo.ru/wp-content/plugins/formcraft/file-upload/server/content/files/160bd949e8fa6b---13966037717.pdfIn PDF document text
    • http://adhdadvisory.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c144b4d090d---pabejebofozinaworakiwedu.pdfIn PDF document text
    • http://guowangcable.com/d/files/levotolirezolav.pdfIn PDF document text
    • https://k2salight.com/wp-content/plugins/super-forms/uploads/php/files/9c713c7017341e5ec4881c90a45ddd15/97977256821.pdfIn PDF document text
    • http://baigeleather.com/userfiles/file/14230462456.pdfIn PDF document text
    • https://rhythmcprandfirstaid.com/wp-content/plugins/super-forms/uploads/php/files/75be834b58290e3d41488228d324c24e/26933481079.pdfIn PDF document text
    • https://autotrans911.com/thread/admin/uploads/file/jobakepavozeduli.pdfIn PDF document text
    • http://erdivigado.hu/userkepek/file/fumose.pdfIn PDF document text
    • https://stefandes.com/wp-content/plugins/formcraft/file-upload/server/content/files/16079ade777850---47641927096.pdfIn PDF document text
    • http://phayaotechno.com/UserFiles/File/20374791481.pdfIn PDF document text
    • http://chothuethietbi.info/img/files/1849269777.pdfIn PDF document text
    • https://usssecuritate.ro/userfiles/file/54752402965.pdfIn PDF document text
    • http://exactblue.com/wp-content/plugins/formcraft/file-upload/server/content/files/160aca77d1b58d---36831720908.pdfIn PDF document text
    • https://lea-inc.com/wp-content/plugins/super-forms/uploads/php/files/ec5e0f0fb6d4e65e5d458a16edd31f2e/jezeduzoxumelaroxope.pdfIn PDF document text
    • https://khangle.vn/uploads/images/files/vamiratobajin.pdfIn PDF document text
    • https://ihotel2b.com/upfiles/editor/files/78501244862.pdfIn PDF document text
    • https://pindimana.in/uploads/file/dajubet.pdfIn PDF document text
    • http://icltindia.in/userfiles/file/20837842976.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_off0000e461.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE461 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000fc78.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFC78 10912 bytes
SHA-256: d0cb9303aada10de019630a50a96a5a6cf6eea4a53f6588b4980ae9f696c5a05
font_02_sfnt_off0001157b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1157B 17140 bytes
SHA-256: 9b9437f432a7c6b9f2a3afad41327cd8f302fadd2914a61807c3339cdfa534fa