Malicious PDF — malware analysis report

Static analysis result for SHA-256 43a4e77aaf6533d0…

MALICIOUS

PDF

87.8 KB Created: 2021-07-08 04:19:39 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-15
MD5: 64475d9b0334cc729dabc18d2c325f5c SHA-1: 94810ea5642c08f3cdd1c5435c0b7f30c87ac269 SHA-256: 43a4e77aaf6533d0e12f8e36467eac5a17fc270911e939676a7d755b139178e4
156 Risk Score

Malware Insights

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

The PDF was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. It contains numerous URLs, many pointing to compromised CMS uploads or disposable hosting, forming a link farm designed to redirect users. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, suggesting it's not intended for direct user reading but rather as a container for malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9942

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://clasesholandes.com/userfiles/file/verukolamalilezo.pdf In PDF document text
    • http://training-solutions.ro/wp-content/plugins/formcraft/file-upload/server/content/files/1607e117a283e9---lanajarimu.pdfIn PDF document text
    • http://icsbc.ru/fuploader//file/xeven.pdfIn PDF document text
    • https://tkquiz.com/userfiles/file/25298349882.pdfIn PDF document text
    • http://xn--80ackbssfuieecff0e8c.xn--p1ai/wp-content/plugins/super-forms/uploads/php/files/6ofct5um62cuig88ba21fekid0/69944211722.pdfIn PDF document text
    • http://www.bestlifepolicy.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/160d925923bbfc---feritopifatefejowudatuxat.pdfIn PDF document text
    • https://asigurareingermania.ro/wp-content/plugins/super-forms/uploads/php/files/f212aj4di0ed5k36frrm6dhprd/fitowopolup.pdfIn PDF document text
    • http://giaoducvietnamtv.com/images/ckeditor/files/48254610339.pdfIn PDF document text
    • http://quickvideo.nl/userfiles/file/49270229804.pdfIn PDF document text
    • https://glass-haus.ru/wp-content/plugins/super-forms/uploads/php/files/c5aeb714d97add71d39b61fe06975e90/widunutanokewopo.pdfIn PDF document text
    • https://xn----8sbaavnccwq4am.xn--p1ai/wp-content/plugins/super-forms/uploads/php/files/91512254313ef427633d1abfe9781ef7/jatupafaxarota.pdfIn PDF document text
    • http://www.insurancedirectcanada.ca/wp-content/plugins/formcraft/file-upload/server/content/files/16085be9556175---detufopemupi.pdfIn PDF document text
    • http://hamdard.com/hamdard/app/webroot/img/ckfinder/userfiles/files/vomelojadinifuketatosaza.pdfIn PDF document text
    • https://dedywiredja.com/wp-content/plugins/formcraft/file-upload/server/content/files/160e02182c8dcd---dutefe.pdfIn PDF document text
    • https://oilbasaro.com/web/images/ckfinder/files/20210707213501.pdfIn PDF document text
    • http://aiskreunion.com/clients/b/b4/b417c2091670ce0b0d78f4b231aea02c/File/4922066592.pdfIn PDF document text
    • http://www.gradur.ba/wp-content/plugins/formcraft/file-upload/server/content/files/16098da2ed0b44---54824831316.pdfIn PDF document text
    • https://spazmedia.com/wp-content/plugins/formcraft/file-upload/server/content/files/160e4444a175fd---32542438701.pdfIn PDF document text
    • http://mitcostruttori.it/userfiles/files/36453714161.pdfIn PDF document text
    • https://hotelristorantenovecento.it/wp-content/plugins/super-forms/uploads/php/files/eedb5da03b7058c20ef85ba9e63f9df2/61222431621.pdfIn PDF document text
    • https://eyetracking.pl/userfiles/file/jikavirodiwukiw.pdfIn PDF document text
    • https://www.mercato.co.za/wp-content/plugins/formcraft/file-upload/server/content/files/160856dd07473e---53633924859.pdfIn PDF document text
    • http://okeefesreef.com/ckfinder/userfiles/files/tipexomofelovuvogu.pdfIn PDF document text
    • https://victorybear-info.com/userfiles/files/bafupasebib.pdfIn PDF document text
    • https://nanyangtextile.com/userfiles/file/xefasava.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/A3Ryygt5BCM/uplcv?utm_term=kafka+on+the+shore+pdf+free+downloadPDF 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_off0000f57e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF57E 10672 bytes
SHA-256: fe2a50b338df49b2d85793533d06bd5b692aa7d63608c7a40cff05b1ddb4b37c
font_01_sfnt_off00010dfe.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10DFE 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00012610.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12610 16880 bytes
SHA-256: 331d1a3abba24c5b98929d695dec55c378a6dcfa8a1dba271a3d949b72e61f2d