Malicious PDF — malware analysis report

Static analysis result for SHA-256 b81e41f4ec3ab502…

MALICIOUS

PDF

80.9 KB Created: 2021-09-20 07:46:53 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: 53eb50d730ac448c6f5a81a83e6f2789 SHA-1: df7ba05963d68d08f71e393d61ca9c2be1ce29fe SHA-256: b81e41f4ec3ab50262e0e417728fc8fe8116eeea7c4e4effb1ca2f02271b7f86
184 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file is identified as malicious by ML classifiers and ClamAV, with multiple heuristics indicating it's a link farm pointing to compromised WordPress sites and disposable hosting. The embedded URLs and the nature of the heuristics suggest a phishing or malware distribution attempt. Although no scripts were extracted, the PDF structure and embedded URLs are indicative of malicious intent, likely leading to a second-stage download or phishing page.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9981

Heuristics 8

  • 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.
  • QR-code redirect lure medium SE_QR_LURE
    Document instructs the user to scan a QR code with a phone — consistent with QR phishing, but also common in legitimate documents
  • Urgency / deadline lure low SE_URGENCY_LURE
    Document contains urgency or deadline language ('account will be terminated', 'action required within 24 hours', etc.) — useful context, but low-signal without other findings
  • 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://synerhu.ru/uplcv?utm_term=inshot+premium+free+ios PDF link annotation
    • https://imapcb.org/wp-content/plugins/super-forms/uploads/php/files/b656ff2e4452721787d5c3dcc15db8db/javikupemenaromup.pdfIn PDF document text
    • http://sudeoksa.com/userfiles/file/20210916145751.pdfIn PDF document text
    • https://drivetripper.com/userfiles2020/files/26804032749.pdfIn PDF document text
    • http://changrung.com/ckfinder/userfiles/files/lovimetegulerudiwakegafun.pdfIn PDF document text
    • http://michalpavlicek.com/uploaded/file/890882141.pdfIn PDF document text
    • http://bundoreh.com/fckeditor/files/file/pedabinalata.pdfIn PDF document text
    • http://jianianhuayule.a9188.com/upload_files/art_files/files/20210903_011504.pdfIn PDF document text
    • http://bluebiz.kr/userData/board/file/bakejemezepunulegovaka.pdfIn PDF document text
    • https://shining4u.com/wp-content/plugins/super-forms/uploads/php/files/16ad89eaf031eed3c263ab5037511326/xisiw.pdfIn PDF document text
    • http://kingsfci.com/userfiles/file/wewojiwasawuzo.pdfIn PDF document text
    • http://ark-mr.com/data/home/qxu2063190031/htdocs/uploadfile/files/88483457171.pdfIn PDF document text
    • http://machulski.com/public/file/vabanaxowadovituzude.pdfIn PDF document text
    • http://www.stockholmswingallstars.com/wp-content/plugins/formcraft/file-upload/server/content/files/161445b6c98fca---lerija.pdfIn PDF document text
    • https://bakotech.at/uploads/ckeditor/files/38488503108.pdfIn PDF document text
    • http://akinmedikal.com/uploads/file/26448112370.pdfIn PDF document text
    • http://betonkeritesek.eu/Content/files/59312243724.pdfIn PDF document text
    • http://1qjd.com/upload/files/2021-09-17-14-17-13-lW5Mrall.pdfIn PDF document text
    • https://coebmsf.com/userfiles/file/jifugupirusu.pdfIn PDF document text
    • https://buyafranchise.org/files/files/24666804542.pdfIn PDF document text
    • http://parfumerieindex.nl/images/uploads/bepewuwekavutewivivotug.pdfIn PDF document text
    • http://savalis.ru/userfiles/file/guwigapezijufu.pdfIn PDF document text
    • http://youngshiny.com/userfiles/file/1631774285.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_off0000d69e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD69E 18380 bytes
SHA-256: 54a47af730c597fd7cf781f9f914ebbe73b518ef534691fb747ea4ca9f666f90
font_01_sfnt_off00010674.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10674 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00011e8b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11E8B 10464 bytes
SHA-256: 44cbeed9d097416aad88c1921b2dc6c02521b7419e6d63dfe18ae9f62c8f56a3

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