Malicious PDF — malware analysis report

Static analysis result for SHA-256 c71bf7ff3aa44669…

MALICIOUS

PDF

87.1 KB Created: 2021-09-05 05:59:59 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: 91ea18c10184e95431ae6c13f5a8ee1d SHA-1: 385e8c7049949d12ab7a7ca75b01f4d344e6ab0d SHA-256: c71bf7ff3aa44669a7dfcb7301c0cf137dce83903144ed802c158167962e84df
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF file was flagged by ML classifiers and ClamAV as malicious, indicating a phishing or trojan threat. It contains numerous links, many pointing to disposable hosting or compromised CMS upload directories, suggesting a link farm designed for SEO poisoning or directing users to malicious content. No scripts were extracted, and the document body was unreadable, but the heuristic findings strongly indicate a malicious intent to redirect users.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9973

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 http://gzmzwl.com/Uploadfiles/files/84943806082.pdf In PDF document text
    • http://anhuishangbiao.com/upload_fck/file/2021-5-2/20210502063427533231.pdfIn PDF document text
    • https://apexforestservices.com/wp-content/plugins/formcraft/file-upload/server/content/files/160774f332b664---97545184536.pdfIn PDF document text
    • http://vantaidongsaigon.com/uploads/files/13287982489.pdfIn PDF document text
    • http://noithatmfc.com/media/ftp/file/kapavasegajixewelinedipud.pdfIn PDF document text
    • http://www.christianhouseshare.com.au/ckfinder/userfiles/files/xurobolemowupe.pdfIn PDF document text
    • http://www.stockholmswingallstars.com/wp-content/plugins/formcraft/file-upload/server/content/files/16081b35ec66ba---4735179335.pdfIn PDF document text
    • http://anaminfo.com/attachfile/file/33494390536.pdfIn PDF document text
    • https://1sis.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607af89863041---wixunu.pdfIn PDF document text
    • http://evopizza.lt/ckfinder/userfiles/files/vedojesusorubosureli.pdfIn PDF document text
    • http://botosani.ro/img/uploads/file/sonij.pdfIn PDF document text
    • http://designbeginnings.com/upload/file/defidabuzofidegatataru.pdfIn PDF document text
    • http://www.fliesen-brill.de/wp-content/plugins/formcraft/file-upload/server/content/files/160ee1dd27cd44---21838159941.pdfIn PDF document text
    • http://cs-web-design.de/ablage/userfiles/files/xijoladabekiboviwilazag.pdfIn PDF document text
    • https://travelsafeway.com/userfiles/file/gepatifusiviwenuxagivex.pdfIn PDF document text
    • https://contactfm.be/userfiles/files/63563207912.pdfIn PDF document text
    • https://condicionamentofisico.com/arquivos/file/46710548677.pdfIn PDF document text
    • http://locthanhwindow.com/img_duhoc/files/73795680786.pdfIn PDF document text
    • http://mnogonomerov.ru/uploads/file/76449173867.pdfIn PDF document text
    • http://umrllc.com/userfiles/files/mifex.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/DOqCt-cVA4I/uplcv?utm_term=bacterial+pigments+pdfPDF link annotation
    • 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 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000d602.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD602 10896 bytes
SHA-256: a6910bd1cf0383746f932a9b9218d2fea597b1b6237b65d826380281d8253aef
font_01_sfnt_off0000eefd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEEFD 16420 bytes
SHA-256: d517165e1bf1a77e8ed580675e50e6e2a99fe6f9ec99be1c35a82b701add332d
font_02_sfnt_off000105af.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x105AF 19252 bytes
SHA-256: 8225b5ad0035f5c3fe76afc07f32da1e786b82d80923159d4a4638d993e1bc56
font_03_sfnt_off000136aa.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x136AA 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1