Malicious PDF — malware analysis report

Static analysis result for SHA-256 553c173eb5972ee2…

MALICIOUS

PDF

75.3 KB Created: 2021-08-22 06:22:19 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: 5a1e5a93eff91470ca6bd2bb34d61282 SHA-1: 43243fdd5745600db4ecf9420fb2c4b7dd504159 SHA-256: 553c173eb5972ee2c4b6cf15b614ea3e639a552590ccb3778e21711a2da30f20
156 Risk Score

Malware Insights

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

The PDF contains numerous external links, many pointing to compromised WordPress upload directories and other disposable hosting. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for phishing or distributing further malware. The document body is heavily obfuscated and unreadable, suggesting an attempt to hide its true purpose.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9992

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 https://laborke.ru/uplcv?utm_term=debraj+ray+development+economics+solutions+manual+pdf PDF link annotation
    • https://alubiasdetolosa.com/files/galeria/files/vuxax.pdfIn PDF document text
    • https://www.medipratik.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609f632e98b9f---lerefikudipavavefi.pdfIn PDF document text
    • https://chicagoportablexray.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c0ce181c22e---vupop.pdfIn PDF document text
    • http://chemicalengineers.ie/images/porugobeguloref.pdfIn PDF document text
    • https://www.lowdoc-loans.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/1609cf6e26ffa8---botozon.pdfIn PDF document text
    • https://mission4recruitment.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609e6369a3940---75465778096.pdfIn PDF document text
    • http://www.deadclan.nl/wp-content/plugins/formcraft/file-upload/server/content/files/16073c17556150---jolaxilujoravupel.pdfIn PDF document text
    • http://jatyn.cn/upfiles/202105/file/1621854518.pdfIn PDF document text
    • http://prunay-en-yvelines.fr/ckfinder/userfiles/files/getevebufapoderekotedik.pdfIn PDF document text
    • http://timavoshipsupply.it/userfiles/file/86559940854.pdfIn PDF document text
    • http://j-club.eu/userfiles/file/81030312051.pdfIn PDF document text
    • http://arcdesantmarti.com/biocop/Images/images-editor/file/lamusunababipilinizifidog.pdfIn PDF document text
    • http://www.davidwoodpersonnel.com/wp-content/plugins/formcraft/file-upload/server/content/files/160af974c0b99d---51025135557.pdfIn PDF document text
    • http://sbhs1967.com/clients/8/89/8985ce50e7417da620f75e2af787291b/File/mirijexisejoxavofug.pdfIn PDF document text
    • http://designklasse.de/ckfinder/userfiles/files/domerebugijabinixev.pdfIn PDF document text
    • http://ednak.com/wp-content/plugins/formcraft/file-upload/server/content/files/160776ff88a36e---86978723004.pdfIn PDF document text
    • http://sangiorgioautoservizi.com/userfiles/files/koxelazozupukulako.pdfIn PDF document text
    • http://asckhn.com/acskhn/userfiles/file/7675834180.pdfIn PDF document text
    • https://klingende-zeder.de/wp-content/plugins/formcraft/file-upload/server/content/files/16104a5997cf6f---nitafowovixufoj.pdfIn PDF document text
    • https://hps-gruppe.com/wp-content/plugins/super-forms/uploads/php/files/u22mng4s57bhgf9qrq8k56mip7/80649191641.pdfIn PDF document text
    • http://lamachine.nl/userfiles/file/42903755630.pdfIn PDF document text
    • https://qualitymattressfactory.com/admin/userfiles/file/zipalixi.pdfIn PDF document text
    • http://szguilong.com/userfiles/files/wirafimapuwadivagata.pdfIn PDF document text
    • http://3e-machinery.ru/app/webroot/filesfiles/68923998063.pdfIn PDF document text
    • 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_off0000c375.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC375 11332 bytes
SHA-256: 68b83f7acdd8e4e2ad75c145eedc1fd6d91c1ad0fb090bdd09121c6e504008a3
font_01_sfnt_off0000dde5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDDE5 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000f5f7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF5F7 15864 bytes
SHA-256: 8b4212eb9167668cd61a0dc855f6b9d5ad306f45479c6cb3c876cf16c75ed690