Malicious PDF — malware analysis report

Static analysis result for SHA-256 81d544342e24bb0a…

MALICIOUS

PDF

78.0 KB Created: 2021-09-19 02:10:28 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 52af8048de083ddd8c9b955841fb8370 SHA-1: a8b4cb52ec8e4fd82012703d266d8599f95a3012 SHA-256: 81d544342e24bb0af69779ac5766fdcc4d47ef389b47b4dee45f8590c4e41007
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. Heuristics reveal it functions as a link farm, directing users to multiple compromised websites, including WordPress upload storage. The presence of numerous external URIs and the PDF_SEO_DISPOSABLE_LINK_FARM heuristic strongly suggest a phishing or malware distribution scheme.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9963

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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 https://catamma.ru/uplcv?utm_term=best+pvp+phone+games PDF link annotation
    • http://nabisori.com/userfiles/file/dabuvizupit.pdfIn PDF document text
    • https://dcimx.com/files/43905245400.pdfIn PDF document text
    • http://bjoybrands.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614657594edbb---79059544079.pdfIn PDF document text
    • http://mnogonomerov.ru/uploads/file/soboxepezubiladiwo.pdfIn PDF document text
    • http://abnig.friendship-match.com/upload/files/85618402289.pdfIn PDF document text
    • http://bibliotekaludwin.pl/img/upload/files/zixuzasuvarafoza.pdfIn PDF document text
    • http://marcus-1.com/FileData/ckfinder/files/20210915_2B5A0F1364F563BA.pdfIn PDF document text
    • http://dalnoboy.org/data/filestorage/upload/files/zexum.pdfIn PDF document text
    • http://cortocircuito.trialpanel.com/images/Upload/files/ruliruxaxopudekux.pdfIn PDF document text
    • http://rivebistro.net/ckfinder/userfiles/files/43544859293.pdfIn PDF document text
    • http://www.blackhillsdancecentre.com/wp-content/plugins/formcraft/file-upload/server/content/files/161466f20af847---rinitifidolurigulamer.pdfIn PDF document text
    • http://rem-stroymont.ru/img/file/65594892283.pdfIn PDF document text
    • http://adirondackseafood.com/ckfinder/userfiles/files/zetogokofapuxajewelude.pdfIn PDF document text
    • https://nomaquito-travel.com/editor-images/batopesubotovugef.pdfIn PDF document text
    • https://daulte.com/ckfinder/userfiles/files/30091232378.pdfIn PDF document text
    • https://iieng.org/editor/ckfinder/userfiles/files/kurenoxofugaviliretuwosi.pdfIn PDF document text
    • https://elger.cz/fckphotos/file/21239678887.pdfIn PDF document text
    • https://peisheng.org/uploads/ckfiles/files/61343f561e43e.pdfIn PDF document text
    • https://ccveg.org/wp-content/plugins/super-forms/uploads/php/files/5ljkmmkhhrdgd4bkdef11121m2/47632605281.pdfIn PDF document text
    • https://ariconium.cz/webpagebuilder/ckfinder/userfiles/files/xutokeroberinel.pdfIn PDF document text
    • http://fisioterapiasuzzara.it/userfiles/files/91478685248.pdfIn PDF document text
    • https://www.meditech.cz/ckfinder/userfiles/files/45038956012.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_off0000cf34.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCF34 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000e74b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE74B 10580 bytes
SHA-256: 6f602d74a6f15db5919e3eda512414934d7e55ea223f861a6d35dc6a8b07eea7
font_02_sfnt_off0000ff5a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFF5A 17044 bytes
SHA-256: 92198f00a0b4958cb18286c05affc5217326d7eb5afcf3b535da509fe4c50952