Malicious PDF — malware analysis report

Static analysis result for SHA-256 4b4c6251455fa3b9…

MALICIOUS

PDF

83.1 KB Created: 2021-09-15 19:53:14 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-24
MD5: 6e8b36d82c2c5b89d11286f6d6271fa2 SHA-1: 9160ed0535204740ff2f45cd9a5cd200451b9a89 SHA-256: 4b4c6251455fa3b95ee6b32d386954f4915c68bacbc7b67ea00ef8585cadbc14
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous embedded URLs, many of which point to compromised CMS uploads or disposable hosting, indicating a link farm designed to redirect users. The ML classifier and ClamAV detection strongly suggest malicious intent, likely related to phishing or malware distribution. Although no scripts were explicitly extracted, the PDF structure and URL patterns are indicative of malicious activity.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9960

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 http://nitexprofi.cz/userfiles/file/26981423076.pdf In PDF document text
    • http://erimti.com/userfiles/file/kopipegolusevofubowigaxog.pdfIn PDF document text
    • http://amkchem.com/upload/files/lurut.pdfIn PDF document text
    • http://gzlmjx.com/data/home/bxu2343160066/htdocs/uploadfile/files/vugokenisovoko.pdfIn PDF document text
    • http://tatvideo.ru/ckfinder/userfiles/files/lujuvirufologaxamerofuma.pdfIn PDF document text
    • http://sns.hu/_user/file/vobutirifugep.pdfIn PDF document text
    • https://sweetestspaparty.com/wp-content/plugins/formcraft/file-upload/server/content/files/16137990966914---73801382227.pdfIn PDF document text
    • http://quatangsongvan.com/hinhanh_fckeditor/file/90611374069.pdfIn PDF document text
    • https://cplastik.eu/data/cms/file/68074281414.pdfIn PDF document text
    • http://studiotecnicobergamaschi.it/userfiles/files/85527321600.pdfIn PDF document text
    • https://jooli.ru/ckfinder/userfiles/files/56825187834.pdfIn PDF document text
    • http://www.dr.schure.net/ckfinder/userfiles/files/43306068781.pdfIn PDF document text
    • http://mid-europe-ex.com/images/blog/file/suvur.pdfIn PDF document text
    • http://www.thelawchamber.com/wp-content/plugins/formcraft/file-upload/server/content/files/161403517143c7---1136402576.pdfIn PDF document text
    • http://cuanhuaabshanquoc.vn/files/83327092712.pdfIn PDF document text
    • https://lakecountyoralsurgery.com/wp-content/plugins/formcraft/file-upload/server/content/files/161408ed6a570d---pefumawavor.pdfIn PDF document text
    • http://snp-ent.com/files/fckeditor/file/91640556861348a2e4d9b8.pdfIn PDF document text
    • https://prevodi-plovdiv.com/userfiles/file/wajik.pdfIn PDF document text
    • http://tropo-design.com/ckfinder/userfiles/files/wotugorazadidasejozamuke.pdfIn PDF document text
    • http://syntrend.critical.tw/upload/files/40052843080.pdfIn PDF document text
    • http://mehmetrasimmutlu.com/icerik/file/59582638989.pdfIn PDF document text
    • http://liveisagenix.com/ckfinder/userfiles/files/20036286684.pdfIn PDF document text
    • http://kht.civilkozpont.hu/uploads/file/dukepedob.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/S30rS-6n6vg/uplcv?utm_term=black+widow+free+online+123moviesPDF 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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000d822.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD822 11180 bytes
SHA-256: 0bcff95d158562407f4494d58a628f4d5f5aa7769502c95736a5d956448c07fe
font_01_sfnt_off0000f27a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF27A 19936 bytes
SHA-256: 3f3cbf596945df2b4e12218d7e4cc71c965b3c87371d5d31cadf9aa2d0f0e9a1
font_02_sfnt_off0001267b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1267B 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1