Malicious PDF — malware analysis report

Static analysis result for SHA-256 8a4b99085946d1bd…

MALICIOUS

PDF

80.4 KB Created: 2021-09-19 17:03:10 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: a04b756ec6f6174ff1e2f2dbccc128af SHA-1: 0428d54ca32aa7b77953edd17cfcdc93546b35b3 SHA-256: 8a4b99085946d1bda828ab5ca19457b21112f596f80bfcc2d4e44314339f7153
156 Risk Score

Malware Insights

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

The PDF file was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, with numerous embedded URLs pointing to compromised or disposable domains. The document body is heavily obfuscated and contains no readable content, suggesting its primary purpose is to host these links rather than convey information.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

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://bestofbeer.ru/ckfinder/userfiles/files/kopuvixokutiva.pdf In PDF document text
    • https://digireg.com/upload/12018304593.pdfIn PDF document text
    • https://casartigianiudine.busletter.it/ckfinder/userfiles/files/32098911745.pdfIn PDF document text
    • http://www.lentilles-progressives.fr/wp-content/plugins/formcraft/file-upload/server/content/files/1613b5830ec66e---rurijevoko.pdfIn PDF document text
    • https://newdesert.pl/userfiles/file/dererisaj.pdfIn PDF document text
    • http://gshosnab.ru/userfiles/file/94542621025.pdfIn PDF document text
    • http://dungcubepgiangtrinh.com/webroot/img/files/6402746436.pdfIn PDF document text
    • http://soles2walk.com/data/file/59533395269.pdfIn PDF document text
    • http://extreamtuning.ru/wp-content/plugins/formcraft/file-upload/server/content/files/16138b928ac611---73190925683.pdfIn PDF document text
    • https://truckforceone.com/upload/editor/file/79495620577.pdfIn PDF document text
    • http://nataliashishkina.com/userfiles/file/3878702047.pdfIn PDF document text
    • http://nemdanangpho.com/uploads/2021-09-16/images/files/wokamibu.pdfIn PDF document text
    • http://miyisz.com/mingyi/images/userfiles/file/73841937841.pdfIn PDF document text
    • http://csc0535.com/userfiles/file/20210916072525_0rt2i1.pdfIn PDF document text
    • https://carcable-bg.com/uploads/pictures/files/bimisalatid.pdfIn PDF document text
    • http://www.olympussverige.se/wp-content/plugins/super-forms/uploads/php/files/takk7n98rcgs33j551i4l0t1m9/fikeresimefezupas.pdfIn PDF document text
    • http://novaserv.com/wp-content/plugins/formcraft/file-upload/server/content/files/16139e736b49f2---segaji.pdfIn PDF document text
    • http://arcdesantmarti.com/biocop/Images/images-editor/file/pogefugutiwapawurito.pdfIn PDF document text
    • http://www.petercar0937494634.com/upload/img/files/18325720312.pdfIn PDF document text
    • http://www.biharikft.hu/bihari-admin/ckfinder/userfiles/files/45078595821.pdfIn PDF document text
    • https://qualitygums.com/userfiles/file/zalurumapowuvonuf.pdfIn PDF document text
    • http://shanghaiqingchen.com/upload/files/58127689134.pdfIn PDF document text
    • https://lisacutler.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613e6945b0f48---zasozivemuwomabupanugi.pdfIn PDF document text
    • http://hidropro.hu/upload/rumifes.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/A3Ryygt5BCM/uplcv?utm_term=developer+option+is+not+available+for+this+userPDF 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_off0000d482.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD482 10764 bytes
SHA-256: 053ce7f9a09932ba2b7cc83caa361bf6875b7bca7b64b211482eda5bc3320cef
font_01_sfnt_off0000ecfa.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xECFA 17828 bytes
SHA-256: 8d6cb90c1b8ede8f341320a1564820f1b4f30e5b53e2f1368a217d89ebcf5483
font_02_sfnt_off00011b5f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11B5F 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1