Malicious PDF — malware analysis report

Static analysis result for SHA-256 50dc7d1d8606f92c…

MALICIOUS

PDF

78.4 KB Created: 2021-09-05 14:46:32 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: 87e5bf58fd2ddca237035f902ab47e62 SHA-1: f4dbe77a7131a35da66a122772838dfb704f0d01 SHA-256: 50dc7d1d8606f92ce5d50f1b7eccab2cf75436c21a06840f86e32c8051f6dee7
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file is identified as a malicious PDF by multiple heuristics and an ML classifier. It contains numerous external links, many pointing to compromised websites or disposable hosting, suggesting a phishing or malware distribution scheme. The presence of PDF_SEO_DISPOSABLE_LINK_FARM and PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM heuristics indicates a deliberate attempt to obscure the true destination or leverage compromised infrastructure. The ClamAV detection further confirms its malicious nature.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9991

Heuristics 7

  • 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.
  • 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://queure.ru/uplcv?utm_term=convertir+xls+a+pdf+en+linea+gratis PDF link annotation
    • https://penzionradvanice.cz/res/file/biwob.pdfIn PDF document text
    • http://longarmquiltacademy.com/fckeditor/userfiles/file/fugazamiparuvu.pdfIn PDF document text
    • http://asiavent.com/UserFiles/file///kufoxupejijikazifime.pdfIn PDF document text
    • https://www.denisonlandscaping.com/wp-content/plugins/formcraft/file-upload/server/content/files/16091490f365ac---62779973847.pdfIn PDF document text
    • https://tootooair.com/FileData/ckfinder/files/20210607_59C4A995587F7F5C.pdfIn PDF document text
    • http://phuocthuan.vn/images/pic/file/39411857124.pdfIn PDF document text
    • https://oncallanatomist.org/ckfinder/userfiles/files/62177849211.pdfIn PDF document text
    • https://apparel.allianceflooring.net/wp-content/plugins/super-forms/uploads/php/files/efdd052c9a9fdbcd0f0fff52dc111ee9/sawonola.pdfIn PDF document text
    • http://russkiivopros.com/images/FCKeditor/file/8957569363.pdfIn PDF document text
    • http://sunrui-ti.com/d/files/11956200824.pdfIn PDF document text
    • http://clinton.abwingsmd.com/uploads/files/68318669641.pdfIn PDF document text
    • http://vizugy.hu/uploads/files/93709690323.pdfIn PDF document text
    • http://www.altrus.pl/wp-content/plugins/formcraft/file-upload/server/content/files/1607ee0853b973---zafamimupisajelol.pdfIn PDF document text
    • https://webmodels.studio/wp-content/plugins/formcraft/file-upload/server/content/files/1607270ce2e594---negolukuvifogiveda.pdfIn PDF document text
    • https://danielstrehlau.com/userfiles/file/47344653695.pdfIn PDF document text
    • http://ascensionchina.com/userfiles/file/47597971679.pdfIn PDF document text
    • http://wrtour.com/FileData/ckfinder/files/20210611_F3B207504E3C3035.pdfIn PDF document text
    • http://www.sbawerribee.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/160ee512211e46---12553344500.pdfIn PDF document text
    • https://maloneslandscape.com/wp-content/plugins/formcraft/file-upload/server/content/files/16080676e0c85d---91975393015.pdfIn PDF document text
    • https://www.popcaffe.it/wp-content/plugins/super-forms/uploads/php/files/c47b5ef7c117197e4792cb2e5a0d7427/72880812568.pdfIn PDF document text
    • 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_off0000c6b9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC6B9 19920 bytes
SHA-256: 25e473c0feb6f1c58dbb084962102ef8afa913969d3cf583a62c45d131958c43
font_01_sfnt_off0000fb05.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFB05 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0001131c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1131C 10872 bytes
SHA-256: 48910eb3639e55314134a70969e1e536225ed92a9e04b05ab38a73d371b4e9ed

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