Malicious PDF — malware analysis report

Static analysis result for SHA-256 99df1c20ff55be10…

MALICIOUS

PDF

79.0 KB Created: 2021-10-05 09:53:46 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-24
MD5: 609d493c53e0e64458e37aadf92e4fbd SHA-1: 800b0d5eea0baed9cdda682b97174fe65f0abcbe SHA-256: 99df1c20ff55be10a9b197f82cf47163679a4d6c9d3361430f9be5c53a813326
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, many of which point to suspicious PDF files on various domains, indicating a link farm. The heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' strongly suggests this is an attempt to manipulate search engine results or distribute malware through a network of linked documents.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9958

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://novelinternationalschool.com/ckfinder/userfiles/files/dodawulijaritoduwafef.pdf In PDF document text
    • https://cambodiadriverservice.com/userfiles/file/wonif.pdfIn PDF document text
    • https://livres-d-art.com/ckfinder/userfiles/files/12095963748.pdfIn PDF document text
    • https://gift-edu.ru/wp-content/plugins/super-forms/uploads/php/files/e94a93f9502280b8c21f42c57dc03f6a/7778538265.pdfIn PDF document text
    • http://sh-songshi.com/admin/upimg/file///2441763739.pdfIn PDF document text
    • http://xn--djr00fsyfv0o5qgy9u.com/filespath/files/20210917114717.pdfIn PDF document text
    • https://centrorevisionimonregalese.it/file/bunovesuwepo.pdfIn PDF document text
    • https://artenika.pl/fck/file/nulexezowurizawowasedowe.pdfIn PDF document text
    • https://ratosatu.com/contents/files/42056090170.pdfIn PDF document text
    • http://decorstore.eu/upload/file/99847401483.pdfIn PDF document text
    • http://viswinkelindex.nl/images/uploads/mawedogolevu.pdfIn PDF document text
    • http://technocom.pl/editor/file/bipijifar.pdfIn PDF document text
    • http://icaalliance.org/filespath/files/20210910004549.pdfIn PDF document text
    • http://detaycopymatbaa.com/userfiles/file/basajefufatugusobuxusejaf.pdfIn PDF document text
    • https://bhavanarayanaswamy.org/userfiles/file/42820767463.pdfIn PDF document text
    • http://rebornfair.com/FileData/ckfinder/files/20210905_3C764734D1E8818A.pdfIn PDF document text
    • https://monyetjoget.com/contents/files/86948679546.pdfIn PDF document text
    • http://boissee.fr/userfiles/file/mekibowin.pdfIn PDF document text
    • http://compagniaviaggi.gattinonimondodivacanze.it/themes/userfiles/files/levisikos.pdfIn PDF document text
    • http://fatename.com/uploads/files/202109221647358146.pdfIn PDF document text
    • https://schmitz.cz/res/file/17147126500.pdfIn PDF document text
    • http://tccsrl.org/userfiles/files/gudopalegobujabe.pdfIn PDF document text
    • http://we2meeting.com/ckfinder/userfiles/publics/files/68882806591.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/BkSY9tpko7c/uplcv?utm_term=percy+jackson+and+the+lightning+thief+online+watchPDF 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_off0000cb3f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCB3F 18560 bytes
SHA-256: a23fe8a70ddca9f6a0fdf352f7d3ea43784b2260a9a92c9dc48308c68fb32042
font_01_sfnt_off0000fc37.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFC37 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0001144e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1144E 11176 bytes
SHA-256: 0a9cad338b35e325834dc042400f61fa192f81f2a50a91ad016e7fd9f0d518cb