Malicious PDF — malware analysis report

Static analysis result for SHA-256 1a238fb01b5f4228…

MALICIOUS

PDF

81.8 KB Created: 2021-05-23 16:01:16 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 52a0a83c470a326fb5db65e3abecd376 SHA-1: b1947ee7baeb0d45b8e0927706fbb4f0c5f825a2 SHA-256: 1a238fb01b5f42283bc2f9cc256949bebcef4148607b163c6d173561144aaf12
156 Risk Score

Malware Insights

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

The file was detected as malicious by ML classifiers and ClamAV, indicating a high likelihood of malicious intent. Several heuristics point to the PDF containing a link farm hosted on compromised CMS uploads, suggesting it's used to redirect users to malicious sites. The document body, though heavily obfuscated, contains references to wkhtmltopdf and creation dates, but no clear user-facing content that would explain its purpose beyond being a 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 http://www.finanzanlagen-honorarberatung.de/wp-content/plugins/formcraft/file-upload/server/content/files/16077e4afdc846---novuviwivudaditiveleje.pdf
    • http://www.chinahkcarplate.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a31023e4c62---85049701772.pdf
    • http://wooshin.kr/uploaded/file/138702213060a376114a344.pdf
    • https://www.synergyheart2heart.team/wp-content/plugins/super-forms/uploads/php/files/luh9pqtms4a0lgipbv76u4ha2l/81171149288.pdf
    • https://smoothnomad.com/wp-content/plugins/super-forms/uploads/php/files/luoifukbb73qboq7vmj3dhfs6s/79620975075.pdf
    • https://agribusiness.pk/wp-content/plugins/formcraft/file-upload/server/content/files/1607509e3ccc2d---fowupimijalox.pdf
    • http://lotuscourtpune.com/wp-content/plugins/super-forms/uploads/php/files/8tj5t252etjicnhi90ic38o5t2/gakonapowutawik.pdf
    • https://gpagroup.in/wp-content/plugins/formcraft/file-upload/server/content/files/16075c63704b8d---39434124233.pdf
    • http://www.greenbriarpropmgmt.com/wp-content/plugins/super-forms/uploads/php/files/ad938a0209aa56a770acb0c224ac3cf5/nitivol.pdf
    • https://www.cdscabling.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/160a9580f046c3---24207503747.pdf
    • http://vipavtoufa.ru/wp-content/plugins/super-forms/uploads/php/files/621491dd21c29d6ee2717570a02ac550/24943418581.pdf
    • https://samiznojmo.cz/wp-content/plugins/super-forms/uploads/php/files/6000dc40dd87ba8733c334523a24cf3b/sogamukafijawokegazib.pdf
    • https://kfz-gutachter-oliver-schiller.de/wp-content/plugins/formcraft/file-upload/server/content/files/1607a5d708eb64---risajakufimegiga.pdf
    • http://intechsol.kz/wp-content/plugins/formcraft/file-upload/server/content/files/16077a6913a3ac---44897402093.pdf
    • http://jeugdopdewetenschapsagenda.nl/wp-content/plugins/formcraft/file-upload/server/content/files/16088d5b79e69d---tulop.pdf
    • http://allaboutdowney.com/userimages/10372855663.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://feedproxy.google.com/~r/Uplcv/~3/fzgW7-mxBc0/uplcv?utm_term=caracter%25C3%25ADsticas+del+conductismo+pdf
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://scripts.sil.org/OFL

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off00010492.bin
6ea0d2e03fa95e81da0c56e0687d894a2eb20029360d86210133e0434d64df2f		 pdf-font-stream PDF embedded font (sfnt) at offset 0x10492 5260 bytes
font_01_sfnt_off00011662.bin
8477affe8f353b554579f4c0078213a1c5d2df5a61ce66db7ecfdadf1a47e479		 pdf-font-stream PDF embedded font (sfnt) at offset 0x11662 11616 bytes

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