Malicious PDF — malware analysis report

Static analysis result for SHA-256 1a2f1cec8b1e34ba…

MALICIOUS

PDF

67.8 KB Created: 2021-06-15 11:03:01 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-14
MD5: d895402fef105a32080223909f44a040 SHA-1: b8cfbcd28649ad5c7814e97fbc8eb460b38d5776 SHA-256: 1a2f1cec8b1e34bae6e9e568e0ada801cca8d645a7fe8ccfb407cf1801163720
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript T1105 Ingress Tool Transfer

The PDF file is detected as malicious by ML classifiers and ClamAV, indicating a phishing or trojan payload. It contains numerous links to compromised websites, suggesting it's part of a link farm designed to host and distribute malicious files. The document body, though heavily obfuscated, appears to be a lure related to English grammar exercises, aiming to trick users into downloading the embedded malicious PDF.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9990

Heuristics 7

  • 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.
  • Visual download / call-to-action button lure low SE_DOWNLOAD_BUTTON
    Document contains a call-to-action phrase ('Click here to download', 'Download Now', etc.) — low-signal unless other findings point to a malicious workflow
  • 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=possessive+adjectives+exercises+perfect+english+grammar PDF link annotation
    • https://artsketch.ru/wp-content/plugins/super-forms/uploads/php/files/34c654ad6659870e9aa6eb76bb1395a5/kuxawazamekuranov.pdfIn PDF document text
    • https://amirep.com/wp-content/plugins/super-forms/uploads/php/files/da649bc28c6d6e8c5a663a3338e5501a/60152116234.pdfIn PDF document text
    • http://africansafaris-spain.com/FCKeditor/editor/filemanager/connectors/php/connector.php?Command=FileUpload&Type=File&CurrentFolder=%252Ffile/gajul.pdfIn PDF document text
    • http://topopentertainment.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a76e4aa8814---96475283191.pdfIn PDF document text
    • https://ecobox.eng.br/wp-content/plugins/super-forms/uploads/php/files/ift2m9ef048dc2q30jv700dp2s/jukiwifotezofepevarowomo.pdfIn PDF document text
    • http://drinkandshrink.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/160c5565e77f26---50662109206.pdfIn PDF document text
    • https://wamsconference.com/wp-content/plugins/super-forms/uploads/php/files/a991324d4e4a02d1bb0ef7457912a60a/vizafejiwazoxozew.pdfIn PDF document text
    • https://www.schroedersales.com/wp-content/plugins/super-forms/uploads/php/files/2d03d7cd52f5a7cc838c4f7ba0c51359/69337435449.pdfIn PDF document text
    • https://swotin.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b8dc611ee9d---77774821471.pdfIn PDF document text
    • https://airshow-bg.com/file/10717547385.pdfIn PDF document text
    • https://sk-developers.com/wp-content/plugins/formcraft/file-upload/server/content/files/16078042fc6c0b---desoxaxogenogamixuvopidod.pdfIn PDF document text
    • http://makaifruits.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609420313ca3e---1349525505.pdfIn PDF document text
    • http://neuragen.ca/wp-content/plugins/formcraft/file-upload/server/content/files/160c7ac46e32cb---gekugi.pdfIn PDF document text
    • http://musikpark-live.de/userfiles/file/xiluxurowutiro.pdfIn PDF document text
    • http://nordicaluminium.ru/userfiles/file/76789640179.pdfIn PDF document text
    • https://carstenrath.com/wp-content/plugins/super-forms/uploads/php/files/h41ei8smi7dmkhovivsv7hidh1/55223065469.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn 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.comIn PDF document text
    • http://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000ce54.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCE54 5776 bytes
SHA-256: acb8dea142e1f5e8a38ca4a4f9cb0792529dda9ec8aedcff18af43e687bd0e83
font_01_sfnt_off0000e1e7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE1E7 10360 bytes
SHA-256: c00525a26844e00ae5d6b40e06fededd7720c70ed6589ce4aafade48a5c552cc