Malicious PDF — malware analysis report

Static analysis result for SHA-256 a98287db8ec4db44…

MALICIOUS

PDF

81.6 KB Created: 2021-09-21 07:48:25 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: ec5fd75d5f5af3a1629afa835ea5e68b SHA-1: 70ad8b418680f21e2331e3ad61931358a885257d SHA-256: a98287db8ec4db44257c99acfc1bfb316e808b9a2c72c990264cccd7f2c42893
156 Risk Score

Malware Insights

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

The file was identified as malicious by ClamAV and an ML classifier, and exhibits characteristics of a link farm. Multiple heuristics indicate the PDF contains numerous external URIs and links pointing to compromised CMS uploads and disposable hosting, suggesting a phishing or malware distribution scheme. The document body is unreadable, but the presence of many URLs on potentially malicious domains supports the attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

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://huntic.ru/uplcv?utm_term=properties+of+integer+exponents+answer+key PDF link annotation
    • http://czdashan.cn/uploadfile/file/2021091910441173499.pdfIn PDF document text
    • https://tepihtrava.rs/files/2533759232.pdfIn PDF document text
    • http://bjsixiang.com/jingkelun/userfiles/files/20210913140720.pdfIn PDF document text
    • https://warsztatgdynia.pl/app/webroot/media/files/mojiwaxavivozudomerawila.pdfIn PDF document text
    • http://boonfagrandhome.com/user_img/files/soxazegaratebiliviwuju.pdfIn PDF document text
    • https://www.bouwenaaneensterkwerkgeversmerk.nl/wp-content/plugins/formcraft/file-upload/server/content/files/1613857fcad4ca---69443425190.pdfIn PDF document text
    • http://gelateriacool.it/userfiles/files/31561545784.pdfIn PDF document text
    • https://tessuno.com/upload/files/6147be0260b13.pdfIn PDF document text
    • http://for-rent-leuven.com/wp-content/plugins/formcraft/file-upload/server/content/files/16139fa415ecf0---71648020698.pdfIn PDF document text
    • https://mn-lawfirm.com/box/userfiles/file/68410689107.pdfIn PDF document text
    • https://vitanov.rs/files/zetasiku.pdfIn PDF document text
    • https://chuyennhakienvangvn.net/upload/files/seruvipugokapoxuwonido.pdfIn PDF document text
    • https://psychotherapie-dr-albrecht.de/wp-content/plugins/formcraft/file-upload/server/content/files/161454b028c065---reludinafo.pdfIn PDF document text
    • http://kazenergy.kz/wp-content/plugins/formcraft/file-upload/server/content/files/1613b4e618ce5b---91544905774.pdfIn PDF document text
    • https://otomatcilarmetal.com/otomat/upload/files/52427617906.pdfIn PDF document text
    • http://cana.vn/uploads/userfiles/file/42738006167.pdfIn PDF document text
    • http://vswet.ru/f/dewowovefutetepadezupetu.pdfIn PDF document text
    • http://jnmindia.com/outscapes/admin/ckeditor/uploads/ck/files/5995230451.pdfIn PDF document text
    • https://meganimal.pt/site/upload/file/35982727464.pdfIn PDF document text
    • http://solarhomepage.ch/fckeditor/editor/images/file/18288784806.pdfIn PDF document text
    • http://eiak.org/upload/editor/files/tezidijokapavaw.pdfIn PDF document text
    • http://metabolitplus.ru/files/file/wazivegekezow.pdfIn PDF document text
    • http://pk.mo/userfiles/file/61839359155.pdfIn PDF document text
    • http://lemma-studio.pl/userfiles/file/vakebuno.pdfIn PDF document text
    • https://karolinanowak.com/userfiles/file/wuzojeb.pdfIn PDF document text
    • 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_off0000d604.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD604 18740 bytes
SHA-256: 9ac3c4c3a2f6c1e546dfae409c057634e4e094254050ec67d6987b049f575e75
font_01_sfnt_off000106b4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x106B4 10884 bytes
SHA-256: e773ecf95f919c5d3acd760206f8e190e655acc4efaa95f137450e6b745048a7
font_02_sfnt_off00012021.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12021 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1