Malicious PDF — malware analysis report

Static analysis result for SHA-256 a8f10ccd57301b32…

MALICIOUS

PDF

87.4 KB Created: 2021-10-06 04:48:27 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-25
MD5: 1655e9fa7605dfac21a1cdef01020d38 SHA-1: c7180150db43b538e82d7d0d38e953db6738d591 SHA-256: a8f10ccd57301b323bb343fe7bd7091e4a5641d9ed6d67ac7cd02eb688db54fa
96 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. The ML classifier strongly indicates maliciousness, and the heuristic firings suggest this PDF is part of a link farm designed to redirect users. The primary purpose appears to be directing traffic to potentially malicious sites rather than exploiting a specific vulnerability within the PDF itself.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9987

Heuristics 5

  • 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://chcial.ru/uplcv?utm_term=archaic+enchanted+ink PDF link annotation
    • http://ingore.cn/upload/files/petewijom.pdfIn PDF document text
    • https://likeevent.it/writable/public/userfiles/file/5888470508.pdfIn PDF document text
    • http://intelekt.biz/uploads/pages/files/diwilidi.pdfIn PDF document text
    • https://partroyfuneralhome.com/partroy/assets/file/savado.pdfIn PDF document text
    • http://opusbiz.kr/data/editor/file/60423203661583260a6e32.pdfIn PDF document text
    • http://datong-travel.tw/upload/ckeditor/files/20210904160716.pdfIn PDF document text
    • http://servmed.net/userfiles/file/vevudademosogebovepo.pdfIn PDF document text
    • http://119pump.net/d/files/xumajubavufa.pdfIn PDF document text
    • https://actor-conseil.com/files/file/977286589.pdfIn PDF document text
    • https://mindweave.co.uk/wp-content/plugins/super-forms/uploads/php/files/m5lrn2fpmqtdi52r62hdken890/49287930741.pdfIn PDF document text
    • https://contemporaryteas.in/admin/uploads/file/guloxawi.pdfIn PDF document text
    • http://setunari.com/uploads/news/2021/09/26/file/99418059863.pdfIn PDF document text
    • http://world-housing.jp/ckfinder/userfiles/files/sivemelujo.pdfIn PDF document text
    • http://svenskafik.se/uploads/fckeditor/file/subor.pdfIn PDF document text
    • https://wlao.on.ca/wp-content/plugins/super-forms/uploads/php/files/0e106acccab3f5710c3cabb6da3d200b/34153151277.pdfIn PDF document text
    • https://hometutorsdelhi.com/userfiles/files/33633404809.pdfIn PDF document text
    • http://alt-1c.ru/userfiles/file/27085193745.pdfIn PDF document text
    • https://sergiomauri.com/images/file/raforuloza.pdfIn PDF document text
    • https://megalight.lv/uploads/files/wetakegavotigok.pdfIn PDF document text
    • http://www.unidacardoso.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/161446360c8512---viragufigifavuva.pdfIn PDF document text
    • https://minhvuongthuphap.com/upload/ck/files/78008971885.pdfIn PDF document text
    • https://hotnews.md/upload/userfiles/files/96224132725.pdfIn PDF document text
    • http://gzpropellers.com/uploadfile/files/gajofuwovumisaredu.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://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_off0000eb2f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEB2F 10204 bytes
SHA-256: 226c0ed2907cf20bd1ea0439b369dc6f5e7b3b92079fadb84d17afdaaf679af3
font_01_sfnt_off00010205.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10205 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00011a17.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11A17 21684 bytes
SHA-256: 7f21df1a64efd5130bc99e01130a4b40b4f291355eac747fe918e5027cf9d3fd