Malicious PDF — malware analysis report

Static analysis result for SHA-256 331c70dfc15bac6b…

MALICIOUS

PDF

81.2 KB Created: 2021-09-21 00:07:42 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: a02f83989bbee2e3e2140d56ad4880ce SHA-1: 8bd7f6de7b1a7db971f900ca0237a360bc05aa55 SHA-256: 331c70dfc15bac6b72e9cecb0dd425a922512f0a85cfdc5c2a4d5a4bf9815d4f
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file was identified as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. Heuristics reveal it functions as a link farm, directing users to multiple external websites, some hosted on compromised CMS uploads. While no scripts were explicitly extracted, the PDF structure and link farm behavior suggest it is designed to redirect users to potentially malicious content, likely for phishing or malware distribution.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9949

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://sungwoo-n.com/userfiles/file/ruronafajotobisenixagemuz.pdf In PDF document text
    • http://raduzhniy.com/wp-content/plugins/formcraft/file-upload/server/content/files/161428c11e3563---57766165436.pdfIn PDF document text
    • http://ibrahimabuomira.com/ckeditor/ckfinder/userfiles/files/duzesekib.pdfIn PDF document text
    • http://zulassungsservice4you.de/bilder/file/39626188152.pdfIn PDF document text
    • https://www.vigo.co.za/wp-content/plugins/formcraft/file-upload/server/content/files/161408b5f793f7---39882473857.pdfIn PDF document text
    • http://rideabikenews.com/user_img/files/50467670255.pdfIn PDF document text
    • https://harpethvalleypto.org/wp-content/plugins/super-forms/uploads/php/files/de8dd2979fa795a75c194d2f5eb3759c/7963421074.pdfIn PDF document text
    • http://krukewittfarms.com/userfiles/file/ladez.pdfIn PDF document text
    • https://twr1115.net/files/fckeditor/file/popagezemiril.pdfIn PDF document text
    • http://pol2-simf.ru/userfiles/file/liwunonutemumipadu.pdfIn PDF document text
    • http://bloomx.com/sites/all/sites/bloomx.com/files/lewutezijiva.pdfIn PDF document text
    • http://tzoetemondje.be/uploads/files/talexoxuxuj.pdfIn PDF document text
    • http://revistaspontan.ro/assets/ckfinder/core/connector/php/uploads/files/94885848088.pdfIn PDF document text
    • https://questyme.ca/userfiles/file/28541670623.pdfIn PDF document text
    • http://le-lemniscus-incandescent.fr/ckeditor/upload/files/52109462671.pdfIn PDF document text
    • http://arisutour.com/ckupload/files/kezinanato.pdfIn PDF document text
    • https://history.tlshaa.org.tw/ckfinder/userfiles/files/letajiwagir.pdfIn PDF document text
    • https://sanagustin.cl/files/gekaxagarapowirife.pdfIn PDF document text
    • https://speedwayinfo.hu/uploads/file/22765569676.pdfIn PDF document text
    • http://xn--80akazwaeiw.xn--p1ai/editorfiles/file/51302909483.pdfIn PDF document text
    • http://brmhn.com/userfiles/file/20210902214716_xrcx20.pdfIn PDF document text
    • http://studiopol.com/userfiles/files/danigaj.pdfIn PDF document text
    • https://worldkelo.com/wp-content/plugins/super-forms/uploads/php/files/27fd0dfb44502c3aec09fa8210680f3f/93191771916.pdfIn PDF document text
    • http://pensjonatagat.pl/userfiles/file/16624879816.pdfIn PDF document text
    • https://mamproducciones.es/wp-content/plugins/formcraft/file-upload/server/content/files/16130d8d620399---22683668820.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/1xuhb7AK25c/uplcv?utm_term=adjectives+to+start+a+sentencePDF 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_off0000da29.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDA29 17416 bytes
SHA-256: 18ce7b797432ff2595b9422d10a69594478cece550f075fad762c986ff92dfdb
font_01_sfnt_off0001072d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1072D 10492 bytes
SHA-256: 63acccdee42cefcdfcb0731ea4977d4dd3918ce59d1e9732b844a65ea5fa8ae1
font_02_sfnt_off00011f29.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11F29 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1