Malicious PDF — malware analysis report

Static analysis result for SHA-256 9133aa353fac81a5…

MALICIOUS

PDF

74.7 KB Created: 2021-09-16 10:53:52 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 61f1cbbe768715d31913d2989047d5f4 SHA-1: 85612fea7bae216534287ef9405da24ac78d77b1 SHA-256: 9133aa353fac81a541044ef3ea54de5c7ea37428d6872bec6d05b80b833eba60
156 Risk Score

Malware Insights

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

The PDF contains a link farm directing to numerous external URLs, with several hosted on compromised CMS upload directories. 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, limiting the analysis of specific user-facing lures.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9976

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://martom24.pl/martom/userfiles/file/4158194391.pdf In PDF document text
    • https://dolphinsolutions.net/ckfinder/userfiles/files/51792352496.pdfIn PDF document text
    • http://freetds.net/userfiles/file/doxabadufu.pdfIn PDF document text
    • http://julianina.dk/upload/file/rejub.pdfIn PDF document text
    • http://quocteanviet.com/img-chamthi/files/73317120117.pdfIn PDF document text
    • http://skrabl.pl/www/rpbd/fck/file/23949189242.pdfIn PDF document text
    • http://joyandwowbook.com/upload/file/rarusezomojadikobibu.pdfIn PDF document text
    • http://erisalaw-chicago.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/ludope.pdfIn PDF document text
    • https://dintek.eu/uploads/file/31033508283.pdfIn PDF document text
    • http://www.hkqi.com/wp-content/plugins/formcraft/file-upload/server/content/files/16141df1e09a43---46642731390.pdfIn PDF document text
    • http://theorientgarden.iorderfoods.com/uploads/files/11143216513.pdfIn PDF document text
    • http://esipro.fr/userfiles/file/88270554853.pdfIn PDF document text
    • https://dulsuc.cl/userfiles/file/xilebevezikogemolebiso.pdfIn PDF document text
    • http://tradeweb.es/userfiles/file/vizakizib.pdfIn PDF document text
    • https://digicpictures.com/downloads/7966637200.pdfIn PDF document text
    • http://stopasbestos.ca/wp-content/plugins/formcraft/file-upload/server/content/files/16142d4ed8d1c2---niges.pdfIn PDF document text
    • http://liweisteel.co.th/ckfinder/userfiles/files/tugomejeke.pdfIn PDF document text
    • http://geology.ie/wp-content/plugins/formcraft/file-upload/server/content/files/1613780ce9fc75---potawamijawox.pdfIn PDF document text
    • http://xn--90ad5ackt1d.xn--p1ai/wp-content/plugins/super-forms/uploads/php/files/a2507dfdd6543647562740dbb7131215/tafexoxu.pdfIn PDF document text
    • https://yumasri.com/assets/ckfinder/userfiles/files/kusimofasuvixotekebalego.pdfIn PDF document text
    • http://mineraux-et-lithotherapie.fr/ckeditor/upload/files/16391590445.pdfIn PDF document text
    • https://westhigienia.hu/editor_up/xadasurad.pdfIn PDF document text
    • http://usaoxin.com/userfiles/2021-9/file/bixeburuzakutovolabiraxi.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/A3Ryygt5BCM/uplcv?utm_term=calories+in+whole+milkPDF 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_off0000c09b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC09B 17292 bytes
SHA-256: 1ba00e042fcd0125db869370c92a181b116e90b9c4f85433946eaefa1fb64723
font_01_sfnt_off0000ed3b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xED3B 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00010552.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10552 10484 bytes
SHA-256: e9a71496638dc12ddbdaa051f9d044ce3b110026200b206a475ef86a0005ce7b