Malicious PDF — malware analysis report

Static analysis result for SHA-256 15e2bfc81fa36ea1…

MALICIOUS

PDF

85.5 KB Created: 2021-09-11 21:30:46 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: c78117af10a1eb08e3c1fcf5538de605 SHA-1: d51cd9f5bc165cdf98434869618a79733dc3c860 SHA-256: 15e2bfc81fa36ea14bcf5be83346cd65489aebda3f54c476ed8e3de358e4e74f
156 Risk Score

Malware Insights

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

The PDF contains a link farm pointing to numerous other PDF files hosted on various domains, some of which are identified as potentially compromised CMS uploads. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for phishing or distributing further malware. No scripts were extracted, and the document body was unreadable, so the rationale is based on the URL analysis and heuristic findings.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9970

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://caudafotografia.com/userfiles/files/rusisogojofe.pdf In PDF document text
    • http://centroolosprato.it/userfiles/files/2009420510.pdfIn PDF document text
    • https://ecohort.info/userfiles/files/93486634342.pdfIn PDF document text
    • http://eros-arena.com/eros/userfiles/file/96004422698.pdfIn PDF document text
    • http://weifong.tw/fckimages/file/sirajubomijopepa.pdfIn PDF document text
    • http://hengfengpaper.com/filespath/files/20210908031915.pdfIn PDF document text
    • https://eric-parnes.shortex.com/ckfinder/userfiles/files/46606599436.pdfIn PDF document text
    • https://paardenwelzijnscheck.nl/app/webroot/files/ckeditor_files/files/worelomusavofonoxapox.pdfIn PDF document text
    • http://vivatbacchus.hu/files/file/31474740511.pdfIn PDF document text
    • http://wujipacking.tw/upload/files/72284076300.pdfIn PDF document text
    • http://www.kissdocs.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/16138e89810c8d---7095263268.pdfIn PDF document text
    • https://balticstroy.com/uploads/files/35837064713.pdfIn PDF document text
    • https://xn--80adj7cxa.xn--p1ai/wp-content/plugins/super-forms/uploads/php/files/eb8016d20dfcc4c195f38a924842e068/puxerepibabapokupar.pdfIn PDF document text
    • http://khiensa.com/UserFiles/File/51741891575.pdfIn PDF document text
    • http://ternovykh.ru/content/file/36811907930.pdfIn PDF document text
    • http://barrarioservicos.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/16139feb8e6b76---96754961905.pdfIn PDF document text
    • https://unitjaya.com/contents/files/xakolapokax.pdfIn PDF document text
    • http://whatifitspossible.com/ckfinder/userfiles/files/60322823856.pdfIn PDF document text
    • https://used-machinetools.ro/app/webroot/files/userfiles/files/47850882292.pdfIn PDF document text
    • https://davidfoleyinc.com/userfiles/file/sosol.pdfIn PDF document text
    • http://apart1day.ru/file/rixedeked.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/ngfLrbzwjls/uplcv?utm_term=fps+shooting+games+for+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_off0000ebe7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEBE7 10876 bytes
SHA-256: 608f3339d547b8fb9c8f43848a63fb3253809e796bacebb1e03b17c1289b8f56
font_01_sfnt_off000104a5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x104A5 17172 bytes
SHA-256: c55decb743a071a52f98818dac0346875d9ae951f7a5b62513814e10cea5f3c5
font_02_sfnt_off000130f5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x130F5 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1