Malicious PDF — malware analysis report

Static analysis result for SHA-256 835a5e9bb841d752…

MALICIOUS

PDF

73.5 KB Created: 2021-09-18 12:53:45 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 0a1a4c32d8b9e98fd6671f30ec4484e5 SHA-1: ebb42bef143202503de88f929fcf0deb38bd5cc2 SHA-256: 835a5e9bb841d752b8b2cf66b1b841203ecedb3726ac16d3c9320d259bed6654
156 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs, many of which point to compromised or disposable hosting, indicating a link farm designed to redirect users to malicious content. The ClamAV detection and ML classifier strongly suggest malicious intent, likely related to phishing or malware distribution. The presence of multiple external URIs and link farm heuristics supports an attack pattern focused on luring users to external sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9951

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 https://wastran.ru/uplcv?utm_term=adfree+tool+apk PDF link annotation
    • http://amunt.madteam.net/ckfinder/userfiles/files/11485683649.pdfIn PDF document text
    • http://etkenkalip.com/files/7979722790.pdfIn PDF document text
    • http://adabaskimerkezi.com/upload/file/72849159641.pdfIn PDF document text
    • https://xn-----6kcabagcgfjsxjciriy6alkh6a7aqk.xn--p1ai/wp-content/plugins/super-forms/uploads/php/files/afdcd4be6a19bdb0943c423135c184b7/45685952338.pdfIn PDF document text
    • http://daedukgs.com/admin/fckeditor/data/file/20210914195600.pdfIn PDF document text
    • https://wlao.on.ca/wp-content/plugins/super-forms/uploads/php/files/9f5e501795196bfdf3926c40f17243b1/67970586989.pdfIn PDF document text
    • https://armagedonspedycja.pl/files/file/nosoxiruk.pdfIn PDF document text
    • https://dongciao.com/uploads/files/202109091750355938.pdfIn PDF document text
    • http://www.melodypods.com/wp-content/plugins/formcraft/file-upload/server/content/files/16130f2edc030f---14424419640.pdfIn PDF document text
    • https://nieruchomosciturystyczne.eu/files/file/76056611251.pdfIn PDF document text
    • http://agedwedfjtj.pretty-match.com/upload/files/14238116719.pdfIn PDF document text
    • https://etadelloro.it/images/file/zagobamidopogov.pdfIn PDF document text
    • https://pelletier-tp.fr/ckfinder/userfiles/files/19905864566.pdfIn PDF document text
    • https://lekkermooi.nl/userfiles/file/julejediluwemotejakam.pdfIn PDF document text
    • https://rippa.pt/files/file/88644514876.pdfIn PDF document text
    • http://chuabenhxuongkhop24h.com/images/files/86184499561.pdfIn PDF document text
    • http://webinaris.blog/ckfinder/userfiles/publics/files/83025649208.pdfIn PDF document text
    • http://vanprodukt.cz/UserFiles/File/85552320223.pdfIn PDF document text
    • https://obermeyer-modemarkt.de/upload/file/getotep.pdfIn PDF document text
    • https://mysmartedu.com/uploadimages/files/kuvidiladeneminuzosakafe.pdfIn PDF document text
    • https://jasz-pap.hu/UserFiles/file/bidituwirede.pdfIn PDF document text
    • https://open-call.fr/uploaded/files/zonigaviti.pdfIn PDF document text
    • http://hpcad.pl/Upload/file/tokid.pdfIn PDF document text
    • https://magatek.com/documents/file/kozavituruxuguzuvimof.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_off0000bd76.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBD76 10200 bytes
SHA-256: b1a38b14a4f684b3b89eb72d69d116124e38470e25f607defa692b656b25ffdb
font_01_sfnt_off0000d47a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD47A 17104 bytes
SHA-256: 196e441bfa8bbb73e330e056ade304a03a6826773a74de0018b3f7c4dc5a2cbb
font_02_sfnt_off000100dd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x100DD 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1