Malicious PDF — malware analysis report

Static analysis result for SHA-256 9951b8820eb16c71…

MALICIOUS

PDF

79.3 KB Created: 2021-09-02 14:31:25 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-05
MD5: 8158c301252271291f5e7f6d984f2bf2 SHA-1: 4910d31f82cbbbf9c1406f5b09e69dfb2542c98d SHA-256: 9951b8820eb16c71cd982858820e203b91946166972b7306ee02b76479bfc258
156 Risk Score

Malware Insights

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

The PDF was flagged by ClamAV as 'Pdf.Phishing.Trojan' and an ML classifier indicated a high probability of maliciousness. Numerous heuristics identified the document as a link farm, with many URLs pointing to potentially compromised CMS uploads or disposable hosting. The primary attack pattern appears to be directing users to external, potentially malicious sites, rather than executing a direct exploit within the PDF itself.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

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://ahkkpcm.org/userfiles/zoxepovotikogugojovanizu.pdf In PDF document text
    • https://ntct-dz.com/ckfinder/userfiles/files/runukoduwirajazefonuvu.pdfIn PDF document text
    • http://cohn-vossen.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c4f6a869ee7---sawekozijexaloligojuvup.pdfIn PDF document text
    • http://www.majoriscambio.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1609ebc8e3fad2---fafakaretoxirirotaf.pdfIn PDF document text
    • https://phase1acoustics.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607043c23d8b7---70227458399.pdfIn PDF document text
    • https://cyklo-wellness-penzion-palice.cz/content/17076573247.pdfIn PDF document text
    • http://theopenhouseclub.com/wp-content/plugins/super-forms/uploads/php/files/43fccb147d4db640761bbc2dd393eb41/diwijifugojutaxe.pdfIn PDF document text
    • https://moniimpex.com/wp-content/plugins/formcraft/file-upload/server/content/files/160d7a44097e6f---92214013391.pdfIn PDF document text
    • http://aliancegroup.su/wp-content/plugins/formcraft/file-upload/server/content/files/160a631a7ec083---bekamogozikugopetiw.pdfIn PDF document text
    • http://www.evisiontiendaonline.com/ckfinder/userfiles/files/66798463813.pdfIn PDF document text
    • http://rayanchem.com/d/files/xomuzezu.pdfIn PDF document text
    • http://cameronhaddock.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608b694c1f2a3---43726129115.pdfIn PDF document text
    • https://mithermomix.com.mx/wp-content/plugins/super-forms/uploads/php/files/6d462978b50b9f17b30dbc209c254fda/21994498843.pdfIn PDF document text
    • https://bluebeakbranding.com/wp-content/plugins/super-forms/uploads/php/files/d1af394a4ebbaf9ade3ab580ef8967bb/gexirizufimokebijab.pdfIn PDF document text
    • http://kuryakyn.ru/userfiles/file/xotoxupijur.pdfIn PDF document text
    • http://bhk-aindling.com/userfiles/files/sagadinakuravofikow.pdfIn PDF document text
    • https://www.lamuccacompany.com/wp-content/plugins/super-forms/uploads/php/files/25012e2acde5232582097a4af949cb32/97482435864.pdfIn PDF document text
    • https://northstarexecutivesearch.com/wp-content/plugins/super-forms/uploads/php/files/a7027f23903d52d06f1fa1f157ddf5c6/diwegubuf.pdfIn PDF document text
    • https://mygamedaysports.com/wp-content/plugins/super-forms/uploads/php/files/597b2b50a1de3b460064bbfb9b3b4716/85806485707.pdfIn PDF document text
    • https://cubic.is/userfiles/file/ruzoruwoxikuzazalikejame.pdfIn PDF document text
    • http://revucue.com/ckfinder/userfiles/files/58440219902.pdfIn PDF document text
    • http://posekatzahradu.cz/files/file/vasepozaxedudetuzugifewu.pdfIn PDF document text
    • https://amalighting.com/wp-content/plugins/super-forms/uploads/php/files/2ca18e2a40358e876e14f83f049564e3/7641473601.pdfIn PDF document text
    • https://www.superioreagle.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606d2951c57d4---97973962875.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/PmAiG5ZyT-k/uplcv?utm_term=siddur+birkat+shelomo+libro+de+rezos+pdfPDF 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_off0000cca2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCCA2 18476 bytes
SHA-256: 94a810382314fcd9a8524f33f16a9130a121b4ed1b3b0f2922b85a75de1d1955
font_01_sfnt_off0000fd42.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFD42 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00011559.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11559 11128 bytes
SHA-256: c0d0347aa84c0e39ad2b3c350b8e15ce00a41d32a734293d4f24d6a7504ec13d