Malicious PDF — malware analysis report

Static analysis result for SHA-256 c0a0b81831b62234…

MALICIOUS

PDF

84.0 KB Created: 2021-09-01 01:31:39 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: dd79a04daca8298e27a4040f20e64fba SHA-1: a911e54e656e4d4ab510cdebeedadd2816a52748 SHA-256: c0a0b81831b62234fbcfef7d9c74c6a4568be9b87570387b77771158b7eee81f
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is identified as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It functions as a link farm, directing users to multiple external PDF files hosted on compromised or disposable domains. The presence of PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM and PDF_SEO_DISPOSABLE_LINK_FARM heuristics suggests a tactic to distribute malicious content through seemingly legitimate or temporary hosting. No scripts were extracted, but the overall structure points to a phishing or malware distribution lure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9991

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://deewo.de/wp-content/plugins/formcraft/file-upload/server/content/files/16095da3181776---zanojuweb.pdf In PDF document text
    • https://delcinfo.ru/img/files/files/82603694687.pdfIn PDF document text
    • https://advicezone.org.uk/wp-content/plugins/super-forms/uploads/php/files/li3ota7pl7vh9ta1l6k4va55b0/rawesugifakelebu.pdfIn PDF document text
    • http://pjzhengwang.com/upload/file/20210721_151419_168.pdfIn PDF document text
    • https://nyig.com/files/file/xudovadinuxawoxan.pdfIn PDF document text
    • https://warsztatgdynia.pl/app/webroot/media/files/89336947419.pdfIn PDF document text
    • http://skupka54.ru/upload/m/juniwufajemixumid.pdfIn PDF document text
    • http://barcelonahotel.vn/UpLoadFile/file/18108832810.pdfIn PDF document text
    • https://rosemonttherapy.health/wp-content/plugins/super-forms/uploads/php/files/jgliftd4ovlceb0ar7eis7hdp5/42384669838.pdfIn PDF document text
    • http://www.anieliasfx.com/uploads/textareas/file/verafurepajove.pdfIn PDF document text
    • http://www.sarajevo-inn-grunewald.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607cd4721745b---senapepive.pdfIn PDF document text
    • http://c2mag.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a340b6ee408---mozoxinavamo.pdfIn PDF document text
    • https://www.edutechusa.com/wp-content/plugins/formcraft/file-upload/server/content/files/160d9756dd5a13---51863323599.pdfIn PDF document text
    • https://adbetelparaguay.com/wp-content/plugins/super-forms/uploads/php/files/75b93c376d695b1167681038da72337d/82935618527.pdfIn PDF document text
    • http://ombs.ru/uploads/files/xevovuxobadawetuzisud.pdfIn PDF document text
    • https://emotionalgift.com/ckfinder/userfiles/files/tugekujatediwi.pdfIn PDF document text
    • http://ipvoicenj.com/wp-content/plugins/formcraft/file-upload/server/content/files/160d264e870d91---15808438294.pdfIn PDF document text
    • http://alimentosldm.com/userfiles/file/39482860131.pdfIn PDF document text
    • http://www.ddu-hk.cz/ckfinder/userfiles/files/40007882260.pdfIn PDF document text
    • http://studioagm.it/userfiles/files/25319601323.pdfIn PDF document text
    • http://biznesfishki.ru/files/userfiles/files/29645569858.pdfIn PDF document text
    • https://laser123.com/geektic/files/rifisetudekovazuruzokev.pdfIn PDF document text
    • http://anhuicrew.com/upload_fck/file/2021-6-2/20210602204702330019.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/3CAf4wW3hvY/uplcv?utm_term=cough+up+yellow+mucusPDF 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_off0000e752.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE752 16596 bytes
SHA-256: 20d5d3c744478bd3cb2ab6422a5e7a305cd5fc640fab76a7b2a9fe634b7451e9
font_01_sfnt_off000111f0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x111F0 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00012a07.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12A07 10596 bytes
SHA-256: 08bbdad5ec9980f3a7d315e906f627b43fb60960bfb49962be0220ab5e5593e8