Malicious PDF — malware analysis report

Static analysis result for SHA-256 ef0c35c5632d400a…

MALICIOUS

PDF

83.0 KB Created: 2021-09-09 08:27:46 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: 93c63d855d707674c28152f6f1327b82 SHA-1: e2b9e572a6a1b44cdb9c6ac141825bccb8e5d0e5 SHA-256: ef0c35c5632d400aa39a75ce08897107b4f7c20f33ec22e2faea5686ee32ec09
172 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a PDF file detected as malicious by ClamAV and an ML classifier. It contains embedded JavaScript and a link farm pointing to external resources, some of which are hosted on compromised WordPress sites. The presence of embedded JavaScript suggests an attempt to execute malicious code, likely for downloading further payloads or redirecting the user to malicious sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

Heuristics 8

  • 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • Visual download / call-to-action button lure low SE_DOWNLOAD_BUTTON
    Document contains a call-to-action phrase ('Click here to download', 'Download Now', etc.) — low-signal unless other findings point to a malicious workflow
  • 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://comillaspostgrado.es/userfiles/file/duguva.pdf In PDF document text
    • http://phanmemerp.vn/attachment/files/nevogodiset.pdfIn PDF document text
    • https://chaletsuenodesol.de/files/kipise.pdfIn PDF document text
    • http://uchid.com/uploads/file/1571767548.pdfIn PDF document text
    • https://www.champagne-cornevin.fr/ckfinder/userfiles/files/jusuvo.pdfIn PDF document text
    • http://kronikarp.pl/ckfinder/userfiles/files/35920032363.pdfIn PDF document text
    • http://ahdongjiu.com/upload_fck/file/2021-9-5/20210905011317581542.pdfIn PDF document text
    • https://ballestermultiservicios.com/wp-content/plugins/formcraft/file-upload/server/content/files/16132d5969a9a4---52503456629.pdfIn PDF document text
    • http://teen.plovdivweek.com/js/ckfinder/userfiles/files/vawililuxanesotozu.pdfIn PDF document text
    • http://refpecsbelvaros.hu/kepek/files/rolazosuzolijawax.pdfIn PDF document text
    • http://chelseacarpet.com/ckfinder/userfiles/uploads/figiraforafaromite.pdfIn PDF document text
    • https://luathoanghuy.com/uploads/files/zofote.pdfIn PDF document text
    • https://gemicilojistik.com/userfiles/upload/file/jasaxazepuzebizefikuk.pdfIn PDF document text
    • http://twilaw.com/files/files/30517009481.pdfIn PDF document text
    • http://tcsklife.com/filespath/files/20210909051840.pdfIn PDF document text
    • http://jadeite.ru/images/file/36775064177.pdfIn PDF document text
    • https://frennphotography.com/wp-content/plugins/formcraft/file-upload/server/content/files/161300970397e2---4514211591.pdfIn PDF document text
    • http://influences-vegetales.eu/assets/Image/files/83374356960.pdfIn PDF document text
    • https://isuzuphonoi.com/data/dulieu/files/75328973613.pdfIn PDF document text
    • http://conwaychristian.org/wp-content/plugins/formcraft/file-upload/server/content/files/16137485e4d67e---mesotajivugo.pdfIn PDF document text
    • https://chorland-dining.com/webroot/editor-uploads/files/rofakefunebukowuxozaz.pdfIn PDF document text
    • http://skrabl.pl/www/rpbd/fck/file/61746112303.pdfIn PDF document text
    • http://kmbb.at/userfiles/file/9864362723.pdfIn PDF document text
    • http://synphabase.ch/upload/file/rijopuzezefuwatare.pdfIn PDF document text
    • http://bukhatirhomes.com/userfiles/file/latoninesaxe.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/1xuhb7AK25c/uplcv?utm_term=candy+manor+apk+modPDF 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_off0000df10.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDF10 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000f722.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF722 18540 bytes
SHA-256: 81f0b019f3419954fa73cf501328a31f61398484ff2c90b394635ab7cc79e674
font_02_sfnt_off0001276f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1276F 10256 bytes
SHA-256: c57a84b8a679beb7b67488f24d16a376b0fdb07732075687bba1ba94e4426707

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