Malicious PDF — malware analysis report

Static analysis result for SHA-256 d81e7a1b9aaa65f8…

MALICIOUS

PDF

83.2 KB Created: 2021-09-06 14:19:44 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: 3a442a8f50cb3366c5d3fbe1b92ca4b0 SHA-1: fc85aaad06a7617921404ffb633a05bb087221e9 SHA-256: d81e7a1b9aaa65f8e43e67027b72970919d7a03de70ee9f97e06f6ad6494197b
156 Risk Score

Malware Insights

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

The PDF file was flagged by ClamAV as a phishing trojan and a machine learning classifier indicated a high probability of maliciousness. Heuristics identified it as a link farm, with many embedded URLs pointing to compromised CMS uploads and disposable hosting. The document body is heavily obfuscated, preventing a clear understanding of its specific lure, but the overall structure and URL analysis strongly suggest an attempt to redirect users to malicious sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9912

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://jiangsutravel.kr/userfiles/files/20210901_193848.pdf In PDF document text
    • http://vieclamquantri.net/upload/files/76814340741.pdfIn PDF document text
    • https://cihangirhotel.com/upload/ckfinder/files/jedafinowodevaxuleket.pdfIn PDF document text
    • http://turhantur.com/turhantur/files/63817801682.pdfIn PDF document text
    • http://7sate.com/filespath/files/20210901033054.pdfIn PDF document text
    • http://www.fliesen-brill.de/wp-content/plugins/formcraft/file-upload/server/content/files/16121df8173987---4901753036.pdfIn PDF document text
    • https://greenturtleproductions.com.au/wp-content/plugins/super-forms/uploads/php/files/8ef04c26c183aad874cca83a35650c0c/vuwor.pdfIn PDF document text
    • http://linhkienhunganh.vn/luutru/files/62686513387.pdfIn PDF document text
    • http://caacoding.net/wp-content/plugins/formcraft/file-upload/server/content/files/16127818090424---13000637090.pdfIn PDF document text
    • https://www.pferde-fuer-unsere-kinder.de/wp-content/plugins/formcraft/file-upload/server/content/files/16087aaee92cf7---mugerivifabolew.pdfIn PDF document text
    • http://ashioke.com/images/library/File/10600390067.pdfIn PDF document text
    • http://www.studiolegalefusimorelli.com/wp-content/plugins/formcraft/file-upload/server/content/files/160caec9e970e9---xuxozot.pdfIn PDF document text
    • http://biondiairsystem.it/userfiles/files/nexabefifilejopoda.pdfIn PDF document text
    • https://www.ediliziaindustriale.com/wp-content/plugins/formcraft/file-upload/server/content/files/160bbd5684b881---lemovadef.pdfIn PDF document text
    • https://web-sila.ru/wp-content/plugins/super-forms/uploads/php/files/3d193df11378a9b62e6f5d1d4113a388/dukobiwuromozezagex.pdfIn PDF document text
    • http://huthamcauquanggiap.com/upload/files/22339862948.pdfIn PDF document text
    • http://vyveva.eu/UserFiles/File/laxorudafugipidutoliduvi.pdfIn PDF document text
    • http://atiksigorta.com/files/gitaxavalo.pdfIn PDF document text
    • http://ahjygjg.com/upload_fck/file/2021-9-6/20210906033500438720.pdfIn PDF document text
    • https://gift-edu.ru/wp-content/plugins/super-forms/uploads/php/files/daaf90d596ade5e5cbb8046a463c8081/dapebukuxiwetolet.pdfIn PDF document text
    • http://riskhedgetech.com/uploaded/file/142067135360ae5fc869f5b.pdfIn PDF document text
    • http://namngonviet.vn/user-/files/32123141459.pdfIn PDF document text
    • http://all-premium.com/user_file/files/xewidetebakabelujebos.pdfIn PDF document text
    • http://lubrifianti-auto.ro/files/file/viromepimozubora.pdfIn PDF document text
    • http://www.ctmmaximoravenna.com/ckfinder/userfiles/files/21573546912.pdfIn PDF document text
    • http://wonsakai.com/uploads/files/pusisotokaneliwito.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/3CAf4wW3hvY/uplcv?utm_term=rex+electrolux+refrigerator+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_off0000e40d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE40D 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000fc24.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFC24 10756 bytes
SHA-256: 2682d670ce8069d92e90b514b5f3620ae5dcc0fadf737c346167f8127abfda0f
font_02_sfnt_off000114e4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x114E4 16796 bytes
SHA-256: faa87416b4081d023e0a80e850b93cd5b6466821cac2a7f4ba6ee8453bb462b5

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