Malicious PDF — malware analysis report

Static analysis result for SHA-256 81286fa42b10370b…

MALICIOUS

PDF

115.1 KB Created: 2021-07-26 04:14:18 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: 8fc2445deead6a733aab3b7068b7d7e3 SHA-1: 5f0b232f762d095de527e05c47acdb52d7ecf982 SHA-256: 81286fa42b10370bd9a9f11438b30f60740ab562c99d2efb4aebe50b365fb54d
156 Risk Score

Malware Insights

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

The PDF contains a large number of links, many of which point to unknown PDF files hosted on compromised CMS upload directories. The ClamAV detection and ML classifier strongly indicate malicious intent, likely for phishing or distributing further malware. The document body is unreadable due to encoding issues, but the heuristics and URLs are sufficient to determine the attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9933

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://aberdeeneyes.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/1609acdff219e9---32630119880.pdf In PDF document text
    • https://nothingbutsafetyglasses.com/userfiles/file/wogimisanu.pdfIn PDF document text
    • http://firmykominkowe.pl/Obrazki/edytor/file/sixixarenofapibudikegogi.pdfIn PDF document text
    • https://amthanhanhsangchinhhang.vn/upload/files/sofisexinumotewemaguni.pdfIn PDF document text
    • http://expertcomptablecourreges.fr/michel_courreges/userfiles/file/92966819004.pdfIn PDF document text
    • https://sasalidayanisma.org/uploads/file/7653206256.pdfIn PDF document text
    • https://amatnieks.lv/pictures/image/725875125.pdfIn PDF document text
    • http://americanewbie.com/userfiles/file/xavidepo.pdfIn PDF document text
    • https://al-wesam.com/userfiles/files/bitajanitujufisam.pdfIn PDF document text
    • https://vicotelecom.vn/static/source/images/file/61748762400.pdfIn PDF document text
    • https://pelicanfinancialnetwork.com/ckfinder/userfiles/files/dilaxudofuxedixaxavomoxoz.pdfIn PDF document text
    • https://www.asahinafunnels.com/wp-content/plugins/super-forms/uploads/php/files/asge19lf5gu54c6kfraiboeq98/nokasir.pdfIn PDF document text
    • https://cvenhancer.com/wp-content/plugins/super-forms/uploads/php/files/191e935b72c1b30d0e3fc2e983962ebb/59175156587.pdfIn PDF document text
    • https://hoffmanowska.pl/wp-content/plugins/formcraft/file-upload/server/content/files/16095453f9b1a3---xigorunimabategadoza.pdfIn PDF document text
    • https://pluviaterra.mx/wp-content/plugins/super-forms/uploads/php/files/e730ec84be9d78a2273e0259760827a2/pifipetirenu.pdfIn PDF document text
    • http://fresh-j.info/images/uploadedimages/file/weburojevusagukapu.pdfIn PDF document text
    • https://macleanpinesdrivingschool.com.au/wp-content/plugins/super-forms/uploads/php/files/958c21b6cd1358facf7039a6986f1d41/81786174746.pdfIn PDF document text
    • http://careerhack.net/wp-content/plugins/formcraft/file-upload/server/content/files/16074934ee5ca9---wejipejonakozufuluzunefez.pdfIn PDF document text
    • https://bayardplaza.co.uk/wp-content/plugins/super-forms/uploads/php/files/nsvbbuv56vt49eqsfqdvmojsit/39757209497.pdfIn PDF document text
    • http://mindentudor.hu/userfiles/file/45284484771.pdfIn PDF document text
    • http://lamachine.nl/userfiles/file/lixepoxujibom.pdfIn PDF document text
    • http://xn--9p4b29dncp2cc6y.net/upload/fckeditor/file/womavasabetizago.pdfIn PDF document text
    • http://beckydavidsonhomes.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c0e4deb91c1---vogulejeja.pdfIn PDF document text
    • https://amkboiler.com/wp-content/plugins/super-forms/uploads/php/files/50a5sbogq9irgvmk6lbgddh93v/95958796475.pdfIn PDF document text
    • http://harasim.cz/uploaded/files/18882722188.pdfIn PDF document text
    • http://celcg.pl/uploaded/file/wupefiposusur.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/GLLx1DTH0VQ/uplcv?utm_term=did+sherlock+fall+in+love+with+irene+adlerPDF 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_off00015e59.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x15E59 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off00017670.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x17670 10816 bytes
SHA-256: 0a7171abf8f4c7633c48a8cc6420e1e891103cae1a49cf9da8da8e3b29e9882a
font_02_sfnt_off00018f62.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x18F62 17256 bytes
SHA-256: 350f357a0a10108d24c1e3d27dbd884d0c23b16a88a5f908dbdc2e3f1ea9efb5