Malicious PDF — malware analysis report

Static analysis result for SHA-256 52c34b18d23499b8…

MALICIOUS

PDF

86.9 KB Created: 2021-09-19 19:11:53 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 90dbb9184623a153a208879b1553c442 SHA-1: 877cc9ac3f79fcaebd87618fb7af76b05d378287 SHA-256: 52c34b18d23499b88129188c36064f21c9ed5c1ca098a23218c37511f9a14c12
156 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs, many of which point to compromised WordPress sites or disposable hosting, indicating a link farm designed to distribute further malicious content. The ML classifier and ClamAV detection strongly suggest malicious intent, likely related to phishing or malware delivery via these linked PDFs. The document body is heavily obfuscated and unreadable, providing no direct content clues.

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 http://radiosalsa.fr/php/rs/filesupload/file/96028091832.pdf In PDF document text
    • http://sk4education.com/ckfinder/userfiles/files/39494160059.pdfIn PDF document text
    • https://seedomoretravel.com/files/files/73995506814.pdfIn PDF document text
    • http://jun-travel.com/userfiles/file/36537058746.pdfIn PDF document text
    • http://secureyun.cn/uploadfile/file///2021090314474942.pdfIn PDF document text
    • https://szabobuszrendeles.hu/files/files/xujogagixanupum.pdfIn PDF document text
    • http://homearcky.nl/userfiles/file/26384336537.pdfIn PDF document text
    • https://esterkins.de/ckfinder/userfiles/files/xiwevuxodubujex.pdfIn PDF document text
    • http://www.1atlanticfunding.com/wp-content/plugins/formcraft/file-upload/server/content/files/16147108e10374---65830728400.pdfIn PDF document text
    • https://www.saenger-ohg.de/wp-content/plugins/formcraft/file-upload/server/content/files/1614214fbcedbf---zelagukamipuxasuzotusodig.pdfIn PDF document text
    • https://limblength-sldf.com/userfiles/file/35916999342.pdfIn PDF document text
    • http://polyacer-ecp.com/userfiles/files/20210905_203149.pdfIn PDF document text
    • https://floraplant.gr/FCKeditor/userimages/file/nafewiwiwanidamoniwupuj.pdfIn PDF document text
    • http://winkeleninzundert.nl/uploadimages/files/xiwikatujoriruvawugowug.pdfIn PDF document text
    • http://newbusan.net/FileData/ckfinder/files/20210909_97A8A3B1A5A11A7C.pdfIn PDF document text
    • http://law885995.com/upload/fckimages/file/lujowuxenidalobivebut.pdfIn PDF document text
    • https://jlgardner.org/home/jlg/public_html/ckfinder/userfiles/files/29729000112.pdfIn PDF document text
    • https://mytshirtcreator.com/app/webroot/files/file/51086933034.pdfIn PDF document text
    • https://mbbs.hr/files/pilupax.pdfIn PDF document text
    • http://studioambienteterritorio.it/userfiles/files/24372458522.pdfIn PDF document text
    • http://assessmentinsight.com/ckfinder/userfiles/files/goxasugulo.pdfIn PDF document text
    • https://noble-worldwide.com/wp-content/plugins/super-forms/uploads/php/files/9e2d32e2d1a434b5a552db8dbe6bf400/tigafivubibupijix.pdfIn PDF document text
    • https://robustbrakes.com/administrator/imagetemp/file/48387515813.pdfIn PDF document text
    • https://riminabda.sk/userfiles/file/28321168922.pdfIn PDF document text
    • http://thaiboxes.com/piceditor/file/61151933328.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/BkSY9tpko7c/uplcv?utm_term=wcc+mod+apkPDF 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_off0000f152.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF152 10020 bytes
SHA-256: aad06fa85e94d6b8e01472128ac30bdece3d7ecd2cc3a2983c2d7baa14f1e9ea
font_01_sfnt_off00010792.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10792 17928 bytes
SHA-256: 61cbf0cb97f0edff45d1010fccbc3fbe6ded0f4a7412b999d5fc0ed1d4ea6af3
font_02_sfnt_off00013614.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13614 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1