Malicious PDF — malware analysis report

Static analysis result for SHA-256 efd57d9bad97ce28…

MALICIOUS

PDF

86.7 KB Created: 2021-09-18 22:22:42 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: af713696fd6f371563ff9f4c48babade SHA-1: 352887587cf792adc425008eda7cb3332a9faa17 SHA-256: efd57d9bad97ce281dd689e2b02b547f665348e5b6bf22a2c790274b402afc2a
156 Risk Score

Malware Insights

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

The PDF was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, directing users to multiple potentially compromised or disposable hosting sites. The document body is heavily obfuscated, preventing a clear understanding of its specific lure, but the overall structure and URL targets suggest an attempt to redirect users to malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9973

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://expobar.vn/app/webroot/files/images/pages/files/zilewu.pdf In PDF document text
    • http://allegroescrow.com/wp-content/plugins/formcraft/file-upload/server/content/files/161404524cfb38---zofekoxiduwapibusevajuxe.pdfIn PDF document text
    • https://tootooair.com/FileData/ckfinder/files/20210908_D22BF21E173FFB36.pdfIn PDF document text
    • http://tiquital.com/documentos/file/58329886722.pdfIn PDF document text
    • http://clearlakesd.org/wp-content/plugins/formcraft/file-upload/server/content/files/16143006d40fb9---70663324656.pdfIn PDF document text
    • http://datcat.vn/2018/file/18653374459.pdfIn PDF document text
    • http://www.mezmat.ru/ckfinder/userfiles/files/17033364711.pdfIn PDF document text
    • https://getracemirates.com/userfiles/files/96195529503.pdfIn PDF document text
    • http://mrs-edu.com/sribati/editor/uploadfiles/teposanafevubedumixedato.pdfIn PDF document text
    • http://newo.ru/files/files/kebujabubexebopizevojaje.pdfIn PDF document text
    • http://for-rent-leuven.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613f86996671e---69375051235.pdfIn PDF document text
    • http://uniradioweb.info/userfiles/files/92966545612.pdfIn PDF document text
    • http://serting.eu/userfiles/files/46273533584.pdfIn PDF document text
    • http://www.birapart.com/wp-content/plugins/formcraft/file-upload/server/content/files/161369ede246ca---93642857243.pdfIn PDF document text
    • https://aawyx.com/sites/default/imageuser/file/tejidigamepogedo.pdfIn PDF document text
    • http://dragonspond.com/uploads/files/45678873071.pdfIn PDF document text
    • http://seasonsblinds.com/uploads/ckfinder/userfiles/files/8756639077.pdfIn PDF document text
    • http://nt-module.ru/ckfinder/userfiles/files/62054075862.pdfIn PDF document text
    • http://asid.rw/userfiles/file/kuwuvelibakebimewamujajos.pdfIn PDF document text
    • http://studiofagiani.eu/userfiles/files/96289021187.pdfIn PDF document text
    • http://erulingua.hu/uploads/content_files/files/detakek.pdfIn PDF document text
    • https://www.adcgrain.com/wp-content/plugins/super-forms/uploads/php/files/4ee2609ca9ce7d18d73e9a30da6b1925/36066616049.pdfIn PDF document text
    • https://cartolmania.it/file/sedilebok.pdfIn PDF document text
    • https://underworldgear.com/upload/users/files/27098791317.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/A3Ryygt5BCM/uplcv?utm_term=editthiscookie+extension+for+chromePDF link annotation
    • 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_off0000ed8e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xED8E 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off000105a5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x105A5 10708 bytes
SHA-256: 3b320bca94e239ad89a053ec82d8908e9b52e76bb6b3e529ec7bd4bfc87333f7
font_02_sfnt_off00011e09.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11E09 18072 bytes
SHA-256: a1e40e65926e5ca9b712aae60a10109ee629e979eaa9764da55491458f37da96

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