Malicious PDF — malware analysis report

Static analysis result for SHA-256 a21db3e761bfca7c…

MALICIOUS

PDF

84.4 KB Created: 2021-09-01 01:31:38 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: a8e3584b0451f0e2273473447b1c1a6d SHA-1: 04c550af7caf72a673a6fab2aaf97b62e90f71bb SHA-256: a21db3e761bfca7c4485530dbd341f901e0f1ca1ffd500a28b730a61550c0700
156 Risk Score

Malware Insights

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

The PDF was flagged by a machine learning classifier and ClamAV as malicious, specifically as a phishing trojan. It contains numerous embedded URLs, many of which point to compromised CMS upload directories or disposable hosting, suggesting a link farm designed to distribute malicious content or phish users. The presence of these links and the overall detection by security tools indicate a likely attempt to lure users to malicious sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9978

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://yangpupark.com/uploadfile/files/zorogasixuwedevokivej.pdf In PDF document text
    • http://www.segurosfacility.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160fca645727a4---74845493166.pdfIn PDF document text
    • http://makaeximworld.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606eaae20982f---lozomenofudasujoru.pdfIn PDF document text
    • http://dulichgiahy.com/upload/file/23652358281.pdfIn PDF document text
    • https://heuresromantiques.com/upload/files/xiruzegifirokulinib.pdfIn PDF document text
    • https://sellerflows.com/wp-content/plugins/super-forms/uploads/php/files/a3431127b5d2be4249a72c24cf5d08ed/berepepagotegi.pdfIn PDF document text
    • http://espacioschillout.es/images/admin/file/jitefi.pdfIn PDF document text
    • http://all-pass.com/folder/editor/file/mebub.pdfIn PDF document text
    • https://pyhm.ca/wp-content/plugins/super-forms/uploads/php/files/o64sao434vhr4qf8t7g1vcnmtd/palolusutederas.pdfIn PDF document text
    • https://chogmai.org/ckfinder/userfiles/files/bowabuxos.pdfIn PDF document text
    • https://laihouston.com/wp-content/plugins/super-forms/uploads/php/files/f71cc015036688304d310350ce0b2553/67547396777.pdfIn PDF document text
    • https://www.hediyevideo.com/wp-content/plugins/formcraft/file-upload/server/content/files/16086271b1c42f---60231404337.pdfIn PDF document text
    • https://allmassage.net/upload/file/20210619203843.pdfIn PDF document text
    • http://alexhofford.com/temp/files/file/solevab.pdfIn PDF document text
    • https://valenciamaids.com/userfiles/files/61101076706.pdfIn PDF document text
    • http://henghuitong.com/jingkelun/userfiles/files/20210811130308.pdfIn PDF document text
    • https://bevelec.com/bevelec/dossierMois/file/fusilatibugudogodafajegen.pdfIn PDF document text
    • https://mraos.com/web/userfiles/file/17779307639.pdfIn PDF document text
    • https://www.jemelectric.com/wp-content/plugins/formcraft/file-upload/server/content/files/160929a1ba1293---79823491352.pdfIn PDF document text
    • https://www.a2zmedical.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/160787f00e7a7f---zabumijugipurexefoworal.pdfIn PDF document text
    • http://gospel-pour-100-voix.com/fichiers/newsletter/file/wolaligomiwowupidakunaw.pdfIn PDF document text
    • http://www.jfac.kr/ckfinder/userfiles/files/poritaxagesoweripudifam.pdfIn PDF document text
    • http://www.fsnn.se/wp-content/plugins/formcraft/file-upload/server/content/files/16070cdbb4b8a1---pozitewasa.pdfIn PDF document text
    • https://trungtammatnamviet.vn/upload/files/41828736453.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/3CAf4wW3hvY/uplcv?utm_term=easy+3d+printing+modeling+softwarePDF 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_off0000e269.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE269 17440 bytes
SHA-256: 72b56dadbf03f08518f8b0aeb02031b3fa294ec6d7e7606116447537681bb695
font_01_sfnt_off00010f07.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10F07 11196 bytes
SHA-256: 02dd7626a70a2f8e4285532120ed5c0ddcdfa138d24f587d7eda24b9fd3ef159
font_02_sfnt_off00012919.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12919 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1