Malicious PDF — malware analysis report

Static analysis result for SHA-256 87f31de68d2f8df1…

MALICIOUS

PDF

80.4 KB Created: 2021-09-19 11:03:20 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: 5a7ed0907d311c1f3711f83d5d62be4c SHA-1: fde3cd68ee9ac2b5eae14edd569e852a04e44c6f SHA-256: 87f31de68d2f8df141ee578a2c7031277b5303d680110875d66bba668be34333
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF file was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. It contains numerous embedded URLs pointing to a link farm, with one URL explicitly identified as a link farm on disposable hosting. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, suggesting it's a wrapper for malicious links rather than user-facing content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9953

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://risme.vn/files/37516556415.pdf In PDF document text
    • https://hamayeshniroo.com/shop/file/pivafepililonifadekapef.pdfIn PDF document text
    • https://finliz.lt/i/File/vubogaxata.pdfIn PDF document text
    • https://kungfuclasshongkong.com/louis/taichi/ckfinder/userfiles/files/33091981066.pdfIn PDF document text
    • http://p-energo.ru/content/file/80890840759.pdfIn PDF document text
    • http://bobas24.pl/Upload/file/womadapizotojukudowot.pdfIn PDF document text
    • http://massimobertoarchitetto.com/userfiles/files/6328512795.pdfIn PDF document text
    • http://autosoftware.company/autoresponders_images/files/taturodagasogomavesapur.pdfIn PDF document text
    • https://loyd.rs/images/file/nuvadelapawalibagodup.pdfIn PDF document text
    • https://portalkucharski.pl/app/webroot/media/files/71137934226.pdfIn PDF document text
    • http://nhasachthunam.com/upload/files/mafosopeliwas.pdfIn PDF document text
    • https://spbmworld.com/anaeter_capital/siteadmin/userfiles/files/43367359462.pdfIn PDF document text
    • http://vertracapital.com/uploads/files/28897062115.pdfIn PDF document text
    • https://beautyyaurient.com/editor_upload/file/zoberinenuwadifufam.pdfIn PDF document text
    • http://cornucopiafrederick.com/uploads/files/47864099315.pdfIn PDF document text
    • https://alternativecarrepair.com/userfiles/file/nugamemapulilemeje.pdfIn PDF document text
    • http://www.fattyweng.com.sg/wp-content/plugins/formcraft/file-upload/server/content/files/16130355e0647d---47840539896.pdfIn PDF document text
    • http://classtool.info/upload/files/kipem.pdfIn PDF document text
    • http://mrtowing.ca/Lawyers/userfiles/file/40816026536.pdfIn PDF document text
    • http://cioccolatogallucci.it/userfiles/file/wubanilalarowaso.pdfIn PDF document text
    • https://balticstroy.com/uploads/files/sezawef.pdfIn PDF document text
    • http://rosg.net/sa_upload/userfiles/file/20210913111956.pdfIn PDF document text
    • http://partnerplus30.ru/images/fornews/files/72502286294.pdfIn PDF document text
    • http://otworz-biuro-podrozy.pl/userfiles/file/xavirapupudomukoma.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/cv9VXjIrmdE/uplcv?utm_term=vpn+tornado+pro+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_off0000cfc1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCFC1 10008 bytes
SHA-256: 6386337c11dcc083efda3dc13ecd556b217d774e52983571b6e830251412481b
font_01_sfnt_off0000e60f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE60F 20964 bytes
SHA-256: 041d7e07cb8c6be3bcdcebf7f8f338b158c1c26cc2cccfd6fa0f8812f5c0cd21
font_02_sfnt_off00011c9a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11C9A 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1