Malicious PDF — malware analysis report

Static analysis result for SHA-256 4f836584b4dcb18b…

MALICIOUS

PDF

77.7 KB Created: 2021-09-18 11:01:07 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: 0db9abf3c28f8c291a0553a8eb8977a5 SHA-1: b579246b0f1a0c8937c60cd8e37986f378675482 SHA-256: 4f836584b4dcb18b3695db2cde511a3e1710441b41283fb3662c2965fb71c413
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file contains embedded JavaScript, a common technique for executing malicious code within PDFs. It also features a link farm pointing to multiple distinct hosts, many of which appear to be compromised WordPress sites or disposable hosting, suggesting an attempt to obscure the final destination. The ClamAV detection and ML classifier further support its malicious nature, likely serving as a phishing lure or a downloader for further payloads.

Machine Learning

  • Nyx PDF Classifier malicious score 0.7086

Heuristics 7

  • 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • External URI info PDF_URI
    PDF contains an external URL action
  • PDF differential parser failed info PDF_DIFFERENTIAL_PARSE_FAILED
    The cross-check parser (pdfminer.six) failed on this file: PDF differential parser failed: PDFSyntaxError. Static heuristics still ran and any of their findings above are valid; only the differential cross-check signal is missing.
  • 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://asqcert.net/files/files/jixuwamuke.pdf In PDF document text
    • http://www.phonefixcomo.com/wp-content/plugins/formcraft/file-upload/server/content/files/161457e408ba81---1235845329.pdfIn PDF document text
    • http://tungalag.mn/userfiles/files/12860919820.pdfIn PDF document text
    • https://xn--fiqa735be48e.com/upload/files/37655499867.pdfIn PDF document text
    • http://clubesquilacoma.com/uploads/files/19818209318.pdfIn PDF document text
    • http://ohmamakitchen.com/uploads/files/papajomilotesozozolopex.pdfIn PDF document text
    • https://myhoorayhealth.com/wp-content/plugins/super-forms/uploads/php/files/d922cd7dab11bcbd487d3b2c13390c35/20202542452.pdfIn PDF document text
    • http://tkhomedeco.com/assets/uploads/ckedit/files/20210905055504.pdfIn PDF document text
    • http://clairerolo.com/userfiles/file/63961549877.pdfIn PDF document text
    • http://nemochem.cn/upload/files/sutajimejorotegodek.pdfIn PDF document text
    • https://landlorddebtadvisory.com/wp-content/plugins/super-forms/uploads/php/files/0e0a234c64b09e4da304f12775bb8b06/77071122404.pdfIn PDF document text
    • http://sushinamu.com/uploads/files/dizuf.pdfIn PDF document text
    • https://beyondpins.com/calisma2/files/uploads/75204227181.pdfIn PDF document text
    • http://mfo-fond.ru/ckeditor/ckfinder/userfiles/Images/files/wuvugiz.pdfIn PDF document text
    • http://www.schule.havonix.com/ckfinder/userfiles/files/68200400728.pdfIn PDF document text
    • http://archpiudue.com/userfiles/files/refaxudibeda.pdfIn PDF document text
    • http://cathyourhair.nl/js/ckfinder/userfiles/files/29757484526.pdfIn PDF document text
    • http://www.aaar.cat/assets/js/ckfinder/userfiles/files/66392409057.pdfIn PDF document text
    • http://amandatour.ru/js/ckfinder/userfiles/files/41197605884.pdfIn PDF document text
    • https://www.renfrewareahealthvillage.ca/ckfinder/userfiles/files/24707261009.pdfIn PDF document text
    • http://fruhmann-elektrotechnik.at/vudimeme.pdfIn PDF document text
    • http://xn----7sbbgprpk7biiq.xn--p1ai/admin/ckfinder/userfiles/files/73424074058.pdfIn PDF document text
    • http://familiehollander.nl/images/uploadedimages/file/64023437792.pdfIn PDF document text
    • http://theydeserveastamp.org/wp-content/plugins/formcraft/file-upload/server/content/files/1613fb6ce4b07c---65786516302.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/Om9ozkHLxGw/uplcv?utm_term=555+meaning+lovePDF link annotation
    • 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_off0000d91d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD91D 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000f12f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF12F 16604 bytes
SHA-256: da0e4b80e254284d196728e2321af807dabc300f3214e80e03bf9bcbc06c065b
font_02_sfnt_off00011bc0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11BC0 10188 bytes
SHA-256: b8d37a38440d2991288e39da05bd8b47fd5bb56e0e98ef7d14fde30da174a221