Malicious PDF — malware analysis report

Static analysis result for SHA-256 21ad173abcbfabce…

MALICIOUS

PDF

67.9 KB Created: 2021-09-21 18:31:30 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 078d9bd5d96e8a849a1335d06b8ac0cf SHA-1: 8d148d9f825267e9d289f0a80ab4db68fd172a16 SHA-256: 21ad173abcbfabce7f1c1017e73ea60337325317227e9d2193ee1f8ff317867b
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous links to external websites, many of which are hosted on disposable domains or compromised CMS uploads, suggesting a link farm designed to redirect users to malicious content. The ML classifier and ClamAV detection strongly indicate malicious intent, likely related to phishing or malware distribution. No scripts were extracted, but the structure and URL patterns are indicative of a phishing lure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9991

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://synerhu.ru/uplcv?utm_term=minecraft+pe+apk+download+android PDF link annotation
    • http://blesk-stroy.ru/userfiles/files/47646280193.pdfIn PDF document text
    • http://kystop.com/wp-content/plugins/super-forms/uploads/php/files/8ba63a69bac7a96b6d35da1851994481/tukikabikiboxara.pdfIn PDF document text
    • http://myphamlulanjina.com/upload/files/61203117823.pdfIn PDF document text
    • https://sportuna.be/ckfinder/userfiles/files/80838724857.pdfIn PDF document text
    • https://cli-kh.com/uploads/files/202109200731064414.pdfIn PDF document text
    • https://peusch.lu/userfiles/files/ziwat.pdfIn PDF document text
    • http://thegoshow.net/userfiles/file/mesipekawepexudosamer.pdfIn PDF document text
    • http://daiichihousing.net/uploads/news_file/59645073002.pdfIn PDF document text
    • http://abwingscolley.com/uploads/files/rumosatolu.pdfIn PDF document text
    • http://thechelseaff.com/user_uploads/files/gexakilulijekoloneb.pdfIn PDF document text
    • http://masonhn.com/d/files/bipuwevemexuv.pdfIn PDF document text
    • http://nhatnguyen.vn/media/ftp/file/51915616797.pdfIn PDF document text
    • http://sirindhorn.net/upload/File/45470799469.pdfIn PDF document text
    • https://www.elektrobetrieb-scholz.de/wp-content/plugins/formcraft/file-upload/server/content/files/16141379d7e3d6---vuxafakegozivopowepebapi.pdfIn PDF document text
    • https://cs-nippon-cp.com/mailmagazine/upload/files/sotasijid.pdfIn PDF document text
    • https://microfocus-realize2020mea.com/wp-content/plugins/super-forms/uploads/php/files/61dd5cf4ca4468c38dbbc17bb3ab4bf0/xobesumakijitifaluka.pdfIn PDF document text
    • http://villaroyalenews.com/userimages/55998887002.pdfIn PDF document text
    • http://mmckno2010.zkosuchdol.info/files/18046234183.pdfIn PDF document text
    • http://srtprogetti.eu/userfiles/files/59113792586.pdfIn PDF document text
    • http://xn--80aejmo0alc.xn--p1ai/ckfinder/userfiles/files/dujenavizafefidegonum.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_off0000ad39.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xAD39 10616 bytes
SHA-256: 9bf09cbd092be3ea5fcda68da2b9fed200d86e89d04d920149d47e6d1fb1cca6
font_01_sfnt_off0000c5a9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC5A9 14580 bytes
SHA-256: 95f8703785a67894bb28a2a10d7fd0b9b32b293d9210f18e672386298527e826
font_02_sfnt_off0000ea1b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEA1B 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1