Malicious PDF — malware analysis report

Static analysis result for SHA-256 8cf81d631f25883d…

MALICIOUS

PDF

71.5 KB Created: 2021-09-15 10:07:01 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: fbeb51b596aa12641694881178260536 SHA-1: 54756b024c6c39bc064487512474c579481bd19b SHA-256: 8cf81d631f25883d5c897df17ef009e4a5f111fb328c72c8a2e5627d6d80436d
156 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs pointing to various domains, many of which appear to be compromised WordPress sites or disposable hosting. The heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' indicates a non-clustered link farm on disposable hosting, and 'PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM' suggests links to compromised CMS upload storage. The ML classifier and ClamAV detection strongly indicate malicious intent, likely phishing or malware distribution via these links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9893

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://allytemp.ru/uplcv?utm_term=best+free+emoji+app PDF link annotation
    • http://barudan.hk/UploadFile/file/20210908232936236.pdfIn PDF document text
    • http://wxeina.com/userfiles/files/19940473282.pdfIn PDF document text
    • https://gentrilieu.vn/userfiles/file/xarutubonokudaxe.pdfIn PDF document text
    • http://aylabawadi.ae/userfiles/file/80718184091.pdfIn PDF document text
    • http://www.sg-callenberg.de/wp-content/plugins/formcraft/file-upload/server/content/files/161410e2b9f71a---10006211578.pdfIn PDF document text
    • https://ooobelkom.ru/ckfinder/userfiles/files/nemoturewokarokelibaveze.pdfIn PDF document text
    • http://www.corazondelsol.es/ckfinder/userfiles/files/60920144799.pdfIn PDF document text
    • http://balaton.varosom.hu/userfiles/files/28848685451.pdfIn PDF document text
    • https://zohopin.com/calisma2/files/uploads/44743111750.pdfIn PDF document text
    • http://samtekelektrik.com/files/25783925646.pdfIn PDF document text
    • http://lichnyiybrand.ru/wp-content/plugins/formcraft/file-upload/server/content/files/1613e58c98aed5---fexikot.pdfIn PDF document text
    • https://fjordancv.info/wp-content/plugins/super-forms/uploads/php/files/0b5d5c7ac32488036f036b3ecd9034e0/regudedak.pdfIn PDF document text
    • http://fecoil.com/userfiles/file/ziwalekapifamiximo.pdfIn PDF document text
    • https://www.tai.gr/wp-content/plugins/formcraft/file-upload/server/content/files/1613d338202dc3---kurutopopadat.pdfIn PDF document text
    • https://iqrainternationalschool.org/_assets/files/78767151315.pdfIn PDF document text
    • http://tiramisu-o.com/yamituki-n/uploads/files/75108397574.pdfIn PDF document text
    • https://munis-roquesalbes.cat/demo/vilalba/imatges/file/fuwafotelenubik.pdfIn PDF document text
    • http://kamienneogrody.com/userfiles/file/14468080342.pdfIn PDF document text
    • http://highspiritsmusic.com/ckfinder/userfiles/files/kevepoxixo.pdfIn PDF document text
    • http://sinostandards.net/upload/files/45485906124.pdfIn PDF document text
    • https://www.saltriot.com/wp-content/plugins/super-forms/uploads/php/files/53f85e6f0f4ccf449e9147b00c3806dc/88035259415.pdfIn PDF document text
    • http://dispensapertutti.com/userfiles/files/jusuripine.pdfIn PDF document text
    • http://al-bandak.com/userfiles/file/gibefatoja.pdfIn PDF document text
    • http://lrm.mcdonalds.ua/ckfinder/userfiles/files/votopinuguj.pdfIn PDF document text
    • http://hoanggiaphatstone.com/upload/files/13546394519.pdfIn PDF document text
    • http://kazenergy.kz/wp-content/plugins/formcraft/file-upload/server/content/files/1613d981ce368f---42475963783.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_off0000b8b3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB8B3 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000d0c5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD0C5 15664 bytes
SHA-256: 0e58a1e0313244baf2417af1daa2f04014a29e05134531e7791d1e070aad22be
font_02_sfnt_off0000f86b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF86B 10552 bytes
SHA-256: 1e6c2ddcacd7115f03aa7ee310b70deccc88b645208705d52e4986376e52eabe

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