Malicious PDF — malware analysis report

Static analysis result for SHA-256 88af73b2a4607608…

MALICIOUS

PDF

79.7 KB Created: 2021-09-18 16:14:12 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: b4c03e4e6fe6fe2901fea9385f8a6a1b SHA-1: dd1c20ab0903a1199f6e3705752794f078d08fee SHA-256: 88af73b2a4607608f6d366bb55488e4957bc0970486f4cbf3e06f36ffb10dda4
156 Risk Score

Malware Insights

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

The PDF contains a link farm with numerous URLs pointing to potentially malicious content, as indicated by heuristics like 'PDF_SEO_DISPOSABLE_LINK_FARM' and 'PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM'. The ML classifier and ClamAV detection strongly suggest malicious intent, likely for phishing or malware delivery. No scripts were extracted, but the structure and URL distribution are indicative of a malicious document.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9953

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://kledingindex.nl/images/uploads/wakususiso.pdf In PDF document text
    • http://archidaldegan.eu/userfiles/files/lexoluzowipatamiterizam.pdfIn PDF document text
    • http://www.hcibatiment.fr/wp-content/plugins/formcraft/file-upload/server/content/files/16138aa745cf52---37961411966.pdfIn PDF document text
    • http://playitdirect.ca/ckfinder/uploadfiles/files/gesileberamenepes.pdfIn PDF document text
    • http://spbi.cz/res/file/raxetamekogu.pdfIn PDF document text
    • http://alotercuman.com/ckfinder/userfiles/files/tetunose.pdfIn PDF document text
    • https://calprin.com/ckfinder/userfiles/files/tokufifedobezubibubuk.pdfIn PDF document text
    • https://rasathantrananotech.com/ckfinder/userfiles/files/13664977730.pdfIn PDF document text
    • http://houtackers.nl/userfiles/file/79046196280.pdfIn PDF document text
    • http://www.salac.cz/ckfinder/userfiles/files/70593483710.pdfIn PDF document text
    • https://srldirect.com/ckfinder/userfiles/files/77002085992.pdfIn PDF document text
    • https://nbretail.com.vn/ckfinder/userfiles/files/kafunubamimavolu.pdfIn PDF document text
    • http://daltan.hu/userfiles/file/kinitokidijuximorinivule.pdfIn PDF document text
    • http://jeyadhurgatemple.com/userfiles/file/15802831237.pdfIn PDF document text
    • http://nsdadventist.org/FCKData/file/dujemisubalomit.pdfIn PDF document text
    • https://quanghuydulich.vn/img_duhoc/files/97871043833.pdfIn PDF document text
    • https://teplitsyoptom.ru/wp-content/plugins/super-forms/uploads/php/files/517449b0c0ac05f99f38eb006f8f1969/90136308031.pdfIn PDF document text
    • https://perfectprojects.ro/userfiles/file/vumila.pdfIn PDF document text
    • http://firesecurity.sk/userfiles/file/rojagufagazirat.pdfIn PDF document text
    • http://nacyc.jp/Upload/file/54491976713.pdfIn PDF document text
    • https://ajwatravel.com/wheelmarine/userfiles/file/69680060229.pdfIn PDF document text
    • http://bpabv.nl/uploadfiles/file/dejevelazazunebi.pdfIn PDF document text
    • https://ceiling.holcom.vn/webroot/img/files/lakurekoxalozuborupaver.pdfIn PDF document text
    • http://lisahyatthealth.com/wp-content/plugins/formcraft/file-upload/server/content/files/1612f3bfd603b5---gurobabugafovu.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/3CAf4wW3hvY/uplcv?utm_term=photo+collage+androidPDF 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_off0000d377.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD377 17896 bytes
SHA-256: 38f83a3447394b40ec0e1b6ec12e10dd2ca1a8a06d62c52e4c7281573a6e2622
font_01_sfnt_off000101ec.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x101EC 10480 bytes
SHA-256: ed78cae4880689a9614c5486f7e52ed84731963d6a2a6f46a770532c970d7a13
font_02_sfnt_off00011978.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11978 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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