Malicious PDF — malware analysis report

Static analysis result for SHA-256 11d1535882f09a35…

MALICIOUS

PDF

76.2 KB Created: 2021-09-10 00:47:09 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: 67f098ac4c9bab005f7a9bb16a75aa2f SHA-1: 7b8fdf0d20433f4527cf31237b9d20daeed45280 SHA-256: 11d1535882f09a35a5e15921ed19569a5928d1be44df2ff593fbc8b032fc405b
156 Risk Score

Malware Insights

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

The sample was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. Heuristics identified it as a link farm pointing to various external PDF files hosted on potentially compromised or disposable domains. The presence of multiple external links suggests a phishing or malware distribution campaign, likely initiated via spearphishing attachment.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9971

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://vrakskodamnetice.cz/file/xoperinem.pdf In PDF document text
    • http://eastendmediation.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/74155899991.pdfIn PDF document text
    • https://goldenlinejsc.com/userfiles/file/talezotegozukumixaxuvez.pdfIn PDF document text
    • http://thepnguyentran.com/media/ftp/file/ditidelifamivikamiramuja.pdfIn PDF document text
    • http://venusland.vn/app/webroot/img/files/bisagarebosus.pdfIn PDF document text
    • https://jaunimodienos.lt/wp-content/plugins/super-forms/uploads/php/files/ret8im66it9udfn071ng5da5a8/wufawafazipoxumifo.pdfIn PDF document text
    • https://www.tahitotfalu.hu/ckfinder/userfiles/files/xasus.pdfIn PDF document text
    • http://www.deco-interieure.com/userfiles/file/jusilekerelo.pdfIn PDF document text
    • https://hosrem.org.vn/ckfinder/userfiles/files/15480166317.pdfIn PDF document text
    • http://vietcem.vn/public/default/ckeditor/files/46659898628.pdfIn PDF document text
    • http://hellnocancershow.com/wp-content/plugins/formcraft/file-upload/server/content/files/1612f8922dd0e7---33679655444.pdfIn PDF document text
    • http://www.pirac.org/wp-content/plugins/super-forms/uploads/php/files/83cae945ccd09f17cd6d9ad024153b36/dusopafosomirujumezul.pdfIn PDF document text
    • http://global-leasing-management.com/uf/file/67618695490.pdfIn PDF document text
    • http://sinoscaform.com/upload/ckimg/files/202109062224015421.pdfIn PDF document text
    • http://mtcongnghiepxanh.com/upload/fckimagesfile/1901869903.pdfIn PDF document text
    • http://ahzgbh.news-read.com/upload/files/93957121738.pdfIn PDF document text
    • http://perseverance.cyou/updatefiles/file/85727372894.pdfIn PDF document text
    • http://kanoonkaraj.ir/dbmanager/filebank/htmlgallery/file///49944841970.pdfIn PDF document text
    • https://hoovermaids.com/wp-content/plugins/super-forms/uploads/php/files/35027898431ed383bad8079c3810590f/jubabobodinub.pdfIn PDF document text
    • http://k-sta.kr/FileData/ckfinder/files/20210901_D0D1B056E0718A14.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/YTWXjIUwRh0/uplcv?utm_term=trolls+movie+online+freePDF link annotation
    • https://bxthirteen.wpengine.com/wp-content/plugins/super-forms/uploads/php/files/30fc6f804b382778f095c812ea18745d/17226392226.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_off0000c69b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC69B 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000dead.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDEAD 17848 bytes
SHA-256: 5e54656cff22af5ea9747be93c22f2f72471e23ffa2afc89dd10c537d62f4ce2
font_02_sfnt_off00010d1e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10D1E 10144 bytes
SHA-256: bf35267d71c68bd8e1ca447c48b9eb2730458871a0bf34861cb214b46d02f682