Malicious PDF — malware analysis report

Static analysis result for SHA-256 7c581dcd2cb9be91…

MALICIOUS

PDF

71.8 KB Created: 2021-09-14 12:25:19 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: 5f7f3bb489c8917ed2a97eec6cf05d39 SHA-1: 3c65257b159745b028653d562564f38d91f2ea43 SHA-256: 7c581dcd2cb9be91f2227eb2014f1a33a6a32e63517f4c55e4ff60dbfad6b63d
166 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript

The file was detected as malicious by ClamAV and an ML classifier, and exhibits characteristics of a link farm. Multiple heuristics indicate the PDF contains links to external, algorithmically generated URLs, suggesting a phishing or malware distribution attempt. The presence of numerous unique hosts and UTM parameters further supports this, pointing towards a spearphishing attachment delivery vector.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9982

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 to algorithmically-generated URL high PDF_RANDOM_URL_LINK
    PDF contains a clickable HTTP(S) link whose host looks algorithmically generated (pronounceable-random labels) and whose path/query carries a long high-entropy token. This is the randomized-redirector pattern of malspam phishing lures — the visible document is only a prompt — not a PDF parser vulnerability.
  • 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://rhoptik.cz/klienti/devel/sneznerolby.cz/ckfinder/userfiles/files/tiruzazusagivolerumek.pdf In PDF document text
    • http://saopauloairporttransfers.com/ckfinder/userfiles/files/wumavigoxuxa.pdfIn PDF document text
    • http://www.rpv-drachten.nl/files/file/firerotefijikava.pdfIn PDF document text
    • http://tuclubcr.com/campannas/file/53822468707.pdfIn PDF document text
    • https://zahidnawaz.com/UploadedImages/image/87935009331.pdfIn PDF document text
    • http://kubkao-kubpla.com/userfiles/files/29944306126.pdfIn PDF document text
    • http://vijyaiprismcrm.com/userfiles/files/93392353388.pdfIn PDF document text
    • https://chokysitohang.com/Uploads/userfiles/files/pururafozudubenizi.pdfIn PDF document text
    • http://kiuruvedenlukio.fi/tiedostot/file/lizovanosaja.pdfIn PDF document text
    • https://dpt-mh.com/uploads/news/files/pajuvulinuk.pdfIn PDF document text
    • https://axlthailand.com/imagexx/files/wuwugubarasomapovan.pdfIn PDF document text
    • https://koetec.com/home/~ptow/public_html/ckfinder/userfiles/files/14400401751.pdfIn PDF document text
    • https://songod.vn/uploads/image/files/buravifegugaxijevujidokad.pdfIn PDF document text
    • http://shortguycentral.com/ck_uploads/files/40536061244.pdfIn PDF document text
    • http://yossy.biz/userfiles/file/37142116238.pdfIn PDF document text
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613915c68d092---poxikowejunax.pdfIn PDF document text
    • https://autotoner123.com/home/autotone/public_html/ckeditortest_WORKING/ckfinder/userfiles/files/mesaxu.pdfIn PDF document text
    • http://op-gold.com/ck_image/files/bekekuno.pdfIn PDF document text
    • https://stthomasorthodoxchurchsouthpampady.com/userfiles/file/48098395305.pdfIn PDF document text
    • https://sproname.com/files/userfiles/files/bobepebopisares.pdfIn PDF document text
    • http://haisushitogo.com/uploads/files/7314880065.pdfIn PDF document text
    • http://allier-genealogie.org/File:/64319340940.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/BkSY9tpko7c/uplcv?utm_term=love+comics+pdfPDF 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_off0000b70d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB70D 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000cf1f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCF1F 16884 bytes
SHA-256: d3421bfd4de5ad1364191ce2b7e0a2e84a4c58f3529bd4ebf947394bb8086e2b
font_02_sfnt_off0000fae7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFAE7 10292 bytes
SHA-256: f7409d465e5ed5083ca557f378c1654da0f4895e4f0bf281b6e3c6e2696bb1cd