Malicious PDF — malware analysis report

Static analysis result for SHA-256 efcaed3977ac22f4…

MALICIOUS

PDF

85.5 KB Created: 2021-09-14 02:55:36 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: d867694f90af4dbd48fb0e5d6b73a555 SHA-1: b500a8a518dd5c5fe636af4b6d3f090b286e08aa SHA-256: efcaed3977ac22f4995213c0bcca58269feb678fccf57f3db22a5072ef747146
156 Risk Score

Malware Insights

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

The PDF was flagged by a malicious ML classifier and ClamAV as a phishing trojan. It contains numerous links, many pointing to external PDFs hosted on potentially compromised or disposable domains, suggesting a link farm designed to redirect users to malicious content. The presence of multiple PDF links and the 'link farm' heuristic indicate a multi-stage attack, likely initiating with spearphishing.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9912

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://phone-server.com/userfiles/file/kobujaweberuno.pdf In PDF document text
    • http://kraemer-duennebacke.de/files/file/donetunaxoladagabilotov.pdfIn PDF document text
    • https://makenie.com/upload/files/27103942270.pdfIn PDF document text
    • http://vwtint.com/userData/board/file/95439421553.pdfIn PDF document text
    • http://schule.havonix.com/ckfinder/userfiles/files/26619348195.pdfIn PDF document text
    • https://stotex.rs/files/wuxenewegejomid.pdfIn PDF document text
    • http://www.lasallelille.com/admin/ckfinder/userfiles/files/malexesamilaxokutamuv.pdfIn PDF document text
    • https://hetodon.com/fckeditorfiles/file/29021366943.pdfIn PDF document text
    • http://icbiz.ru/userfiles/file/82833958485.pdfIn PDF document text
    • http://xn--80aer5aza.xn--19-kmcm3c.xn--p1ai/ckfinder/userfiles/files/nesasujubu.pdfIn PDF document text
    • https://rallstarawards.us/nbloom/fckuploads/file/37177415962.pdfIn PDF document text
    • http://driver-jazda.pl/upload/file/73429820239.pdfIn PDF document text
    • https://hexema.com/FCKeditor/file/52309678573.pdfIn PDF document text
    • https://xn--hjrnskadeakademien-mtb.se/userfiles/file/famusolifotekejosevamoke.pdfIn PDF document text
    • http://nutronicltd.com/userfiles/file/2229630814.pdfIn PDF document text
    • http://atel-j.nl/uploads/files/soveporuzura.pdfIn PDF document text
    • https://evrenmentese.com/upload/ckfinder/files/99738943261.pdfIn PDF document text
    • https://rpaxis.net/userfiles/file/fegipemezimotaditujukegu.pdfIn PDF document text
    • http://phunphu.com/userfiles/file/fukivofogup.pdfIn PDF document text
    • https://sk-developers.com/wp-content/plugins/formcraft/file-upload/server/content/files/16136acdd39e8b---41979918767.pdfIn PDF document text
    • https://hmv.ir/wp-content/plugins/formcraft/file-upload/server/content/files/1613fd8c546ffe---88408717227.pdfIn PDF document text
    • http://jolanyee.com/upload/files/202109102229043919.pdfIn PDF document text
    • http://globalnetworks.de/www.galabau-poscher.de/main/preview/ckfinder/userfiles/files/deraloxap.pdfIn PDF document text
    • http://waxiangyuan.com/upload_fck/file/2021-9-7/20210907110814898685.pdfIn PDF document text
    • https://sidexsideaudio.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613d3350c3060---gulilar.pdfIn PDF document text
    • http://tzoetemondje.be/uploads/files/vivepivavolizinawul.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/3vuEKuznOb8/uplcv?utm_term=create+avatar+on+androidPDF 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_off0000e9de.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE9DE 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off000101f0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x101F0 18104 bytes
SHA-256: 0c0941dd0bb7d73ef5a4bbca1eb9e7b09e8a2d15a7df52fe643ebaf8b3fccf9b
font_02_sfnt_off00013122.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13122 10124 bytes
SHA-256: f4e5ddd6b019cc1eacb6e19702c110474714d03ea2b1fa36106aef5e874a67e2

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