Malicious PDF — malware analysis report

Static analysis result for SHA-256 b1852531b554324b…

MALICIOUS

PDF

83.6 KB Created: 2021-10-12 01:09:52 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-24
MD5: 00c77e5e48e5755fa57abb0b84d3c289 SHA-1: 293857241583bdf69c9748672290c57e74bc5e0a SHA-256: b1852531b554324b2144d44a2966bf1bc03ae112ff6da0f2abf116b1e0c312e7
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, with many URLs pointing to potentially compromised websites or disposable hosting. The document body is heavily obfuscated and contains metadata suggesting it was generated by wkhtmltopdf, a tool often used to create PDF versions of web pages, which aligns with the link farm behavior.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

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://annekienlen.fr/imagesfile/93654582883.pdf In PDF document text
    • http://traiteur-ribot.fr/userfiles/file/navibokagupobubazito.pdfIn PDF document text
    • http://protok.pro/upload/files/46279789643.pdfIn PDF document text
    • http://ammk.sk/userfiles/file/87529388308.pdfIn PDF document text
    • http://straps.by/ckfinder/userfiles/files/tokapixabizapivig.pdfIn PDF document text
    • http://microsolder.hu/userfiles/files/55527835479.pdfIn PDF document text
    • http://for-rent-antwerp.com/wp-content/plugins/formcraft/file-upload/server/content/files/16132135ad2663---23748432120.pdfIn PDF document text
    • https://sabunwangi.com/contents/files/81660250822.pdfIn PDF document text
    • https://lee-trading.tw/archive/upload/files/warunaxegurutabuvatow.pdfIn PDF document text
    • http://boldino-hotel.com/ckfinder/userfiles/files/lokalerisu.pdfIn PDF document text
    • http://historia-bfured.hu/userfiles/file/26956935889.pdfIn PDF document text
    • http://mzch.pl/userfiles/file/paniniga.pdfIn PDF document text
    • http://bzws.zhanyougame.com/ckfinder/userfiles/files/lesiwixetupizejibu.pdfIn PDF document text
    • https://www.domaine-boussard-chablis.fr/ckfinder/userfiles/files/zinajotopimutu.pdfIn PDF document text
    • https://sistemagestiondpr.co/userfiles/file/4680621303.pdfIn PDF document text
    • http://poornasreehomeoclinic.com/ckfinder/userfiles/files/bezudolirotatowifovokok.pdfIn PDF document text
    • https://ijtm.in/userfiles/file/lumiludapemo.pdfIn PDF document text
    • http://classicalgardenfountains.com/uplds/file/zososajorokamixupi.pdfIn PDF document text
    • https://mediabandit.com/wp-content/plugins/formcraft/file-upload/server/content/files/161326189c5d8d---fugumajidoji.pdfIn PDF document text
    • http://4seasonstours.in/userfiles/file/39698992962.pdfIn PDF document text
    • http://sangiorgioautoservizi.com/userfiles/files/64894017963.pdfIn PDF document text
    • https://regalcabs.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/161626641ee263---gobogogerofogufujuregizu.pdfIn PDF document text
    • https://zhongzing.com/uploads/files/202109231104391974.pdfIn PDF document text
    • http://wcsps.com.tw/ckfinder/userfiles/files/41287470953.pdfIn PDF document text
    • https://bestcoloringpages.com/userfiles/file/10205398419.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Gsjc/~3/BcFPVxLj4jw/uplcv?utm_term=quarter+of+a+cord+of+woodPDF 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_off0000de1d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDE1D 10304 bytes
SHA-256: c5b9760a8a5a799760ea0213cfcf8348ccc535703374c9418b426bdf2b007695
font_01_sfnt_off0000f5a5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF5A5 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00010db7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10DB7 19508 bytes
SHA-256: 6d9ae6c5d0340ac21094937799a146523ed45cb021570ade27804988dadd548d