Malicious PDF — malware analysis report

Static analysis result for SHA-256 4e99ab83504d1f61…

MALICIOUS

PDF

77.0 KB Created: 2021-08-29 09:04:46 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: 66ffa4f7cb04d15fabb715a10795252e SHA-1: c311cddf49c6750499698a886ec13a645990a235 SHA-256: 4e99ab83504d1f610f19a27d792daaf0ceb771f407efddd987a79b21d8a21720
156 Risk Score

Malware Insights

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

The PDF contains a link farm pointing to numerous other PDF files hosted on various domains, several of which are identified as compromised CMS upload storage. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for phishing or distributing further malware. No scripts were extracted, and the document body was unreadable, so the rationale is based on the URL analysis and heuristic findings.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9983

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://i-daa-wl.de/userfiles/zitodamalanitoniv.pdf In PDF document text
    • http://www.serenissimaservizi.com//files/wajokijirag.pdfIn PDF document text
    • https://codecs.ro/images/file/34669386025.pdfIn PDF document text
    • http://muszempilla.com/files/file/30223474402.pdfIn PDF document text
    • http://qianxish.com/ckfind_image/files/vetofoxil.pdfIn PDF document text
    • http://iwish-cosmetics.com/wp-content/plugins/formcraft/file-upload/server/content/files/161131a925222f---75246027478.pdfIn PDF document text
    • https://brod-plovdiv.com/images/boliroziserugodedasevafo.pdfIn PDF document text
    • http://seanbittinger.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/diluwotigebakuliwos.pdfIn PDF document text
    • https://autosaloncenter.com/uploads/file/wojefironogedawo.pdfIn PDF document text
    • https://lisacutler.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607e9f13111f5---6548877902.pdfIn PDF document text
    • https://desertflying.club/wp-content/plugins/formcraft/file-upload/server/content/files/16129d660296ec---xalogepujob.pdfIn PDF document text
    • https://www.goldenplanet.dk/wp-content/plugins/formcraft/file-upload/server/content/files/16090640ba8475---sepeniv.pdfIn PDF document text
    • https://onlineadda.net/ckfinder/userfiles/files/38424674621.pdfIn PDF document text
    • https://www.baileysmilk.com/wp-content/plugins/super-forms/uploads/php/files/48e1ca8e2d1c2442ccdbc8c3c1742d65/9764503753.pdfIn PDF document text
    • http://amsaneeraus.fi/userfiles/files/xosasil.pdfIn PDF document text
    • http://sllight.ru/design/img/upload/file/3227479440.pdfIn PDF document text
    • https://aquatrustfina.com/userfiles/file/70697309069.pdfIn PDF document text
    • http://deurwater.com/wp-content/plugins/formcraft/file-upload/server/content/files/160aa128ec240c---zowarepa.pdfIn PDF document text
    • http://unicorn-furnitures.com/d/files/195901272.pdfIn PDF document text
    • http://th-hl.com///upload/files/99453125378.pdfIn PDF document text
    • https://smobiil.eu/userfiles/files/25915078802.pdfIn PDF document text
    • http://topopentertainment.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608ccf0425cf3---miwotubizimobekubizika.pdfIn PDF document text
    • http://chiangmai-clean.com/user_img/files/dobaramezez.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/1KS0DP0cxss/uplcv?utm_term=i+oh+i+am+falling+for+you+fallin+for+youPDF 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_off0000c7bf.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC7BF 17824 bytes
SHA-256: 3a1f8cf3ec87a18cabf67daeee6fb475c607ef35427ad3e73ea456df8c44cda9
font_01_sfnt_off0000f574.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF574 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00010d8b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10D8B 10428 bytes
SHA-256: 428d2bf527cc9364c0ad8ff89ea415a915c582678ac0f35aa880dd94263a6377