Malicious PDF — malware analysis report

Static analysis result for SHA-256 ac8745d55b666201…

MALICIOUS

PDF

87.7 KB Created: 2021-09-23 17:04:20 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: 9c4b6f67a918dcacb44895326d70a0f3 SHA-1: 12ad5e5ba3c2fa81b23cac04191fce99897e3aa6 SHA-256: ac8745d55b6662010052a5def4a9d2218cf38e6d449332c2c67da2afc5856114
156 Risk Score

Malware Insights

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

The file was identified as malicious by ML classifiers and ClamAV, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, with many embedded URLs pointing to potentially compromised or disposable hosting. The document body is heavily obfuscated, preventing a clear understanding of its direct user-facing content, but the overall structure and URL analysis strongly suggest a phishing or malware distribution attempt.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9973

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://flairpens.ru/uploads/files/bezufujo.pdf In PDF document text
    • https://sensiblemachines.com/ckfinder/core/connector/php/files/80095344652.pdfIn PDF document text
    • http://www.sunarsurdurulebilir.com/wp-content/plugins/super-forms/uploads/php/files/96g72olcflno2f7467ufd571j7/fupegok.pdfIn PDF document text
    • http://agppi99.pretty-match.com/upload/files/84254355746.pdfIn PDF document text
    • http://www.studiolegalefusimorelli.com/wp-content/plugins/formcraft/file-upload/server/content/files/16138060de2bbd---kuferikolenemit.pdfIn PDF document text
    • http://brukikostka.pl/uploads/page/file/tomoka.pdfIn PDF document text
    • http://agataklimowska.pl/userfiles/file/3169724920.pdfIn PDF document text
    • https://www.nhabe.com.vn/ckfinder/userfiles/files/vadibegagarawusosir.pdfIn PDF document text
    • http://dxqzx.com/ckfinder/userfiles/files/20210907_064916.pdfIn PDF document text
    • https://topinsolventa.ro/userfiles/file/67108921535.pdfIn PDF document text
    • http://szkolaprywatnaleszno.pl/userfiles/file/tixixivofozova.pdfIn PDF document text
    • https://paidionresearch.com/userfiles/files/58115412683.pdfIn PDF document text
    • http://siddharpeedam.org/userfiles/file/In PDF document text
    • http://mweb.cz/images/file/gazok.pdfIn PDF document text
    • http://vivaldiskibus.com/FileData/ckfinder/files/20210918_64459D0C994B3D81.pdfIn PDF document text
    • https://www.afoa.org.ar/backend/ckfinder/userfiles/files/8723818335.pdfIn PDF document text
    • https://www.booster-p.com/wp-content/plugins/formcraft/file-upload/server/content/files/1612fc100388d4---46452970467.pdfIn PDF document text
    • http://forglory.cz/ckfinder/userfiles/files/nafesalujuwusapesapivog.pdfIn PDF document text
    • http://kronospan-mofa.hu/editor_up/medobefosewelajuxuzup.pdfIn PDF document text
    • http://ketphatthinh.vn/upload/files/dusatulinukobusunuwovir.pdfIn PDF document text
    • http://quick-thailand.com/images/uploads/file/sisaxugobanori.pdfIn PDF document text
    • https://chorland-dining.com/webroot/editor-uploads/files/50794530218.pdfIn PDF document text
    • http://aliguoriarchitetto.eu/userfiles/files/xolizurasoxiwafewejo.pdfIn PDF document text
    • http://avtrak.ru/ckfinder/userfiles/files/livajokosurobasade.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/FevRqgeaUVY/uplcv?utm_term=android+tcp+server+examplePDF 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_off0000ee6b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEE6B 10824 bytes
SHA-256: ff32781364088ca76995cfa93916b68eb1e488116d10525a3e087d5daa7dfa83
font_01_sfnt_off0001076a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1076A 19020 bytes
SHA-256: 383c6e80f55ddf6393a733aabdcb7199769aef84756369343dadde6468bcb89a
font_02_sfnt_off00013913.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13913 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1