Malicious PDF — malware analysis report

Static analysis result for SHA-256 b77eb88785cd22e6…

MALICIOUS

PDF

87.9 KB Created: 2021-09-01 09:30:15 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 49ce5b79bcd4cc526efb52f7ee5bbc63 SHA-1: fb1e174adcae39c7603458750f5ea35ebd297071 SHA-256: b77eb88785cd22e688736063aa71294c623962f443649e255cd62762169394a9
156 Risk Score

Malware Insights

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

The PDF contains a link farm pointing to numerous PDF files hosted on compromised CMS uploads. The ML classifier and ClamAV detection strongly indicate malicious intent, specifically identified as phishing or a trojan. The document body is heavily obfuscated and appears to be non-readable content generated by wkhtmltopdf, rather than user-facing text.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9886

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 http://www.kidnuri.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a9a00a13513---99777618799.pdf In PDF document text
    • http://birzebbugastpetersfc.com/files/file/norinimad.pdfIn PDF document text
    • http://spadhotel.com/basefile/spadhotelcom/files/wuwivalodaxixafolalab.pdfIn PDF document text
    • https://anmimar.com/royal/userfiles/file/55654165202.pdfIn PDF document text
    • https://kalatranslation.co.uk/wp-content/plugins/super-forms/uploads/php/files/00jin7lv43vhce3oo2nkp7e2tf/jixesaloligidudurasibof.pdfIn PDF document text
    • http://casaatlantida.com/userfiles/file///62949593263.pdfIn PDF document text
    • http://betheaskssd.com/flash/betheaskssd.com/file/risisubekifobi.pdfIn PDF document text
    • http://shop-cartuning.pl/userfiles/file/sobefovidi.pdfIn PDF document text
    • http://twfindia.in/userfiles/files/gelisapetubasa.pdfIn PDF document text
    • http://admio.ru/wp-content/plugins/formcraft/file-upload/server/content/files/160ad5a62b955f---gekoxupisusipabagamu.pdfIn PDF document text
    • http://xn--or3bi2da319p.com/upload/fckeditor/file/ridotip.pdfIn PDF document text
    • http://arsvet.ru/img/upload/ruzefegolebelutivuram.pdfIn PDF document text
    • https://laihouston.com/wp-content/plugins/super-forms/uploads/php/files/803a6d879404662fbebbce4d259ef3a1/75578631727.pdfIn PDF document text
    • https://buka.ru/sadm_files/89714615477.pdfIn PDF document text
    • https://travelstore.tn/userfiles/file/60845304172.pdfIn PDF document text
    • https://amenajarisiconstructii.ro/wp-content/plugins/formcraft/file-upload/server/content/files/1608790b0c4426---seritavujomowusijuwuge.pdfIn PDF document text
    • http://xn--90aoa5aj.xn--p1ai/ckfinder/userfiles/files/zumulemobuduvep.pdfIn PDF document text
    • http://www.marcado.ca/wp-content/plugins/formcraft/file-upload/server/content/files/1609baeeda03f6---23733552917.pdfIn PDF document text
    • https://www.d-table.com/wp-content/plugins/super-forms/uploads/php/files/0c30797258fff52509211bbeef6ea378/46067774939.pdfIn PDF document text
    • https://phunhai.net/upload/files/tarigedemaz.pdfIn PDF document text
    • https://rebates.forex/wp-content/plugins/super-forms/uploads/php/files/9do3n6usjf8hvi7r5p0mk73ha5/bikab.pdfIn PDF document text
    • https://global-product.org/CKEdit/upload/files/luwopesovav.pdfIn PDF document text
    • http://www.tsahimmongol.com/uploads/images/files/zewukulusawotorofurik.pdfIn PDF document text
    • https://flomogroup.com/upload/files/fozosedikiwi.pdfIn PDF document text
    • https://evenimentecastel.ro/wp-content/plugins/super-forms/uploads/php/files/plr12t1j7aj361lhilcuakukck/80943129314.pdfIn PDF document text
    • https://www.lenoir-elec.com/wp-content/plugins/super-forms/uploads/php/files/dggpu43kivdsk3es40c9i6fqn8/valuwaw.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/cv9VXjIrmdE/uplcv?utm_term=basic+life+support+for+healthcare+providers+manualPDF 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_off0000ee4f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEE4F 17856 bytes
SHA-256: db6da95b19e5a22af80e26a43cd7d07110a8d7338718c35332d67ff435dc1183
font_01_sfnt_off00011c38.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11C38 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0001344f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1344F 11104 bytes
SHA-256: 7568efa03526a73c27c2e576945f0dba7c185c19f48d52668af0aae0967a78c1