Malicious PDF — malware analysis report

Static analysis result for SHA-256 91b65c45bf9c1be0…

MALICIOUS

PDF

84.5 KB Created: 2021-09-12 06:34:25 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: 811ea15f277c8461b876778a2cebdd1c SHA-1: 8d099f3ec71aa775c2d2ccf90d3e55cbbc64b743 SHA-256: 91b65c45bf9c1be05b6cf0088ff7a53b16a0b8d5d26a7f79080e79dc7349bfaf
96 Risk Score

Malware Insights

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

The PDF contains a large number of embedded URLs, many of which point to disposable or compromised hosting domains, indicating a link farm designed to redirect users. The ML classifier strongly flagged this PDF as malicious, and heuristics identified it as a link farm on disposable hosting and potentially pointing to compromised CMS upload storage. No scripts were extracted from this sample.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9951

Heuristics 5

  • 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://corkpotters.com/images/zelabawirexumolowazeke.pdf In PDF document text
    • http://sjhrz.com/images/upload/File/pubezosefidozafudo.pdfIn PDF document text
    • http://bsp-oblspl.org/ckfinder/userfiles/files/fobulavafozobisupo.pdfIn PDF document text
    • http://daotaoyduoc.org/wp-content/plugins/super-forms/uploads/php/files/79c17c560b9eee7f9af42f6cc9b0d04b/gufevarisizegutek.pdfIn PDF document text
    • https://eltonltd.ru/sites/default/files/uploads/roraneroziputopawuti.pdfIn PDF document text
    • https://yp05.com/_UploadFile/Images/file/winirewezuxili.pdfIn PDF document text
    • https://8cj2aja7-8mxb.com/contents/files/52456168700.pdfIn PDF document text
    • http://mateuszkucharski.pl/admin/file/41581515792.pdfIn PDF document text
    • http://sjar-tech.com/uploadfile/file///2021091004362269.pdfIn PDF document text
    • http://www.xpresswedding.com/wp-content/plugins/formcraft/file-upload/server/content/files/16134631b91847---vorovodenek.pdfIn PDF document text
    • https://contemporaryteas.in/admin/uploads/file/32192729094.pdfIn PDF document text
    • http://oikoscoccatoarchitettura.com/userfiles/files/96120025486.pdfIn PDF document text
    • http://kozhencherrymtc.org/userfiles/file/mitomod.pdfIn PDF document text
    • http://kammed.com/userfiles/file/mevuzukadixefopasorixo.pdfIn PDF document text
    • https://benmoonpharma.com/userfiles/file/dufitagimonino.pdfIn PDF document text
    • http://swvocal.com/data/se2/file/83669784798.pdfIn PDF document text
    • http://lnshiyue.com/userfiles/file/20210907190702_1364361794.pdfIn PDF document text
    • http://tysons-cafe.com/uploads/files/82461508726.pdfIn PDF document text
    • https://aviseco.ro/userfiles/file/4340076054.pdfIn PDF document text
    • http://bright-mineral.com/uploadfile/file/2021090918024859.pdfIn PDF document text
    • http://zensushialiso.com/uploads/files/1773148216.pdfIn PDF document text
    • http://gu-bo.cn/uploads/files/31818807082.pdfIn PDF document text
    • https://ocvirapuato.com.mx/wp-content/plugins/super-forms/uploads/php/files/ae6b417e7f49dd2cd6dd82fafb85ab7d/27573294881.pdfIn PDF document text
    • https://zerling.eu/nico/images/files/70971758307.pdfIn PDF document text
    • http://charivne.info/images/file/18781131331.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/YTWXjIUwRh0/uplcv?utm_term=android+virtual+machine+for+macPDF 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_off0000e14a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE14A 19724 bytes
SHA-256: 2f5fc13505c3c2ba6e94b09c410231de65b562e0a5f7ba306173a84ec0e45356
font_01_sfnt_off0001142a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1142A 10720 bytes
SHA-256: ce56b9431594f245174a28021059e5e94489306eb0d07a75d568b4966f79d8ef
font_02_sfnt_off00012c9c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12C9C 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1