Malicious PDF — malware analysis report

Static analysis result for SHA-256 77fbe54f7ac5dd16…

MALICIOUS

PDF

84.0 KB Created: 2021-09-04 15:29:34 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-07
MD5: 4e229d499ab60c70743c689545965011 SHA-1: 48092ed13e068b6c73813d822d5240fe4abb0378 SHA-256: 77fbe54f7ac5dd1615c37cadacdf2d7512a25649158f147705a41b818c9e9a20
156 Risk Score

Malware Insights

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

The PDF file was flagged by a machine learning classifier and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, with numerous embedded URLs pointing to compromised WordPress sites and disposable hosting, likely intended to lure users to malicious content. 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 0.9977

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 https://cutletsmeat.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609e6ae45b9d6---71235248358.pdf In PDF document text
    • http://marmaraisg.com/images_upload/files/61801910.pdfIn PDF document text
    • https://giraffeng.net/infodaily/gen-ckfinder/userfiles/files/kunikip.pdfIn PDF document text
    • https://member-amz-seller-system.de/wp-content/plugins/super-forms/uploads/php/files/0242fc4d13deabef2ca88445e3df71f7/33167504463.pdfIn PDF document text
    • http://www.miamiairportlimo.net/wp-content/plugins/formcraft/file-upload/server/content/files/160f1d0c0cd678---dinexipixomuvibub.pdfIn PDF document text
    • https://aawyx.com/sites/default/imageuser/file/67622224970.pdfIn PDF document text
    • http://hoigolfbinhthuan.com/users/files/wunava.pdfIn PDF document text
    • https://creativesilhouettes.ca/wp-content/plugins/formcraft/file-upload/server/content/files/1606d62df79e1d---dajofarofowe.pdfIn PDF document text
    • https://sarenpinler.com/calisma2/files/uploads/luginuja.pdfIn PDF document text
    • http://braintradingbcn.com/wp-content/plugins/super-forms/uploads/php/files/e12255d8d62bb7cf80d8ce2e02bec32d/kerumunuxegevetemadat.pdfIn PDF document text
    • http://dastone.ru/userfiles/file/lowomebaxot.pdfIn PDF document text
    • https://humanistbeauty.com/wp-content/plugins/super-forms/uploads/php/files/o8j3fa4hsi7p6s85meh9o89ocr/93421344224.pdfIn PDF document text
    • https://jdbailbonds.com/wp-content/plugins/super-forms/uploads/php/files/536f217647633e124b5fbdab801a100b/666111681.pdfIn PDF document text
    • http://hanasushimenifee.com/uploads/files/bavixexoxuvofitamor.pdfIn PDF document text
    • https://www.skyline-recruiting.com/wp-content/plugins/super-forms/uploads/php/files/0ebf4c4a0a16e20a4311e930abbf20a5/43918801815.pdfIn PDF document text
    • https://kaowei.tw/image/files/20210728_073054.pdfIn PDF document text
    • http://fly.no1-yes.com/userfiles/file/55973831801.pdfIn PDF document text
    • https://abyway.lv/images/ck_images/files/71059563073.pdfIn PDF document text
    • https://www.mclarenpress.com/wp-content/plugins/formcraft/file-upload/server/content/files/16097ff1671a28---bilukutumifuv.pdfIn PDF document text
    • https://www.davidwoodpersonnel.com/wp-content/plugins/formcraft/file-upload/server/content/files/160734abe9a035---bekalamakejuwi.pdfIn PDF document text
    • http://krikrik.ru/uploads/ckfinder/files/11949309780.pdfIn PDF document text
    • https://faprosid.com/file/30610218927.pdfIn PDF document text
    • https://biocoils.com/img/file/29040208203.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/6naE_Nh8_CY/uplcv?utm_term=fledermauskasten+selber+bauen+pdfPDF 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_off0000e265.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE265 18320 bytes
SHA-256: 4eee7a652d24c0500c8613cd0f0ee66332bce6c2ca1f87decaceed9f13485beb
font_01_sfnt_off00011001.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11001 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00012818.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12818 10756 bytes
SHA-256: 3b881c60069538fbc8457c878606e7180cbc38b131db7fa705c5cb85ddb4cb7a