Malicious PDF — malware analysis report

Static analysis result for SHA-256 bb6dc65fef82abb8…

MALICIOUS

PDF

81.9 KB Created: 2021-09-21 23:45:22 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: 08105e0ff73fa1f496e8ec084436cab8 SHA-1: 60dc9f0d8e20d2e1da4bc785222fa862296a7a7b SHA-256: bb6dc65fef82abb84b2a68079cf06091738ffe7ad185ee099d900af68b9dcae4
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF was flagged by multiple heuristics, including a critical ClamAV detection for 'Pdf.Phishing.Trojan' and an ML classifier indicating maliciousness. The presence of numerous external URIs, many pointing to disposable hosting and configured as a link farm, strongly suggests a phishing or malware distribution attempt. The document body, though heavily obfuscated, contains metadata indicating it was generated by wkhtmltopdf, a tool often used to create malicious PDFs.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://chcial.ru/uplcv?utm_term=free+online+smarty+bubble+game PDF link annotation
    • https://rsun.pro/admin/ckfinder/userfiles/files/44954200183.pdfIn PDF document text
    • http://xn--80akij1ajew.xn--p1ai/wp-content/plugins/formcraft/file-upload/server/content/files/161373a6903f9c---zawizun.pdfIn PDF document text
    • http://noithatsah.com/webroot/img/files/41206469187.pdfIn PDF document text
    • http://adams-gold.ru/archive/image/file/63126383257.pdfIn PDF document text
    • http://ulv-fogger.ru/d/files/89362152339.pdfIn PDF document text
    • http://coolscape.info/images/files/robudodeworovav.pdfIn PDF document text
    • http://usatovl.ru/upload/fckeditorfile/sulibakavupidererotavu.pdfIn PDF document text
    • https://stl-log.com/htdocs/cljr/data/files/15094827548.pdfIn PDF document text
    • http://salkim.com/userfiles/file/rukutuviterawunudofi.pdfIn PDF document text
    • http://zdrowejaja.com/Upload/file/33478375370.pdfIn PDF document text
    • http://life-homeshop.com/asset/uploads/files/5574606671.pdfIn PDF document text
    • http://townofwinslowin.com/flash/townofwinslowin.com/file/xexatelowir.pdfIn PDF document text
    • http://jedzenie365.pl/ckfinder/userfiles/files/78436958809.pdfIn PDF document text
    • http://hoangnampte.vn/quangbasanpham/app/webroot/upload/image/files/76826052226.pdfIn PDF document text
    • http://baoveantam.org/upload/files/nimugexufavuto.pdfIn PDF document text
    • https://sabagdasarov.ru/upload/file/59156320485.pdfIn PDF document text
    • http://uhy-th.com/image/upload/files/joxiror.pdfIn PDF document text
    • http://nenkin-t.com/upload_img/ck/files/94473020781.pdfIn PDF document text
    • https://horizontire.com/userfiles/file/44837025554.pdfIn PDF document text
    • https://groupburuemas1.com/contents/files/govuvezijup.pdfIn PDF document text
    • https://www.helpagesl.org/wp-content/plugins/formcraft/file-upload/server/content/files/1613cd00991861---lopibaxizoluzosu.pdfIn PDF document text
    • https://dabanbep.tanglehadong.com/upload/files/2049286094.pdfIn PDF document text
    • http://abacusnancy.com/userfiles/file/dusokewiniw.pdfIn PDF document text
    • http://orlickachata.cz/files/files/witimilafititulenotiwibin.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_off0000da38.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDA38 10780 bytes
SHA-256: 4eb469aeddd69479955cd13f9b9c6b8818384cdf7078791f42d793f226280717
font_01_sfnt_off0000f308.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF308 17788 bytes
SHA-256: c28105afe9708a9f61ac9002a4d3191a0f9cc66af5940e998f446d0ab06be0d3
font_02_sfnt_off00012173.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12173 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1