Malicious PDF — malware analysis report

Static analysis result for SHA-256 9221ab251637b1b7…

MALICIOUS

PDF

88.3 KB Created: 2021-09-14 21:09:22 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: e790469cff29facc12e8594b738ee4f7 SHA-1: 8617da8884ea8f652d21228895bb94f6be224d87 SHA-256: 9221ab251637b1b7f0378a94e2274a0f26d5220e6dc9adb4acd2dc0f19c6ccbe
96 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains a large number of embedded URLs, many of which point to compromised CMS uploads or disposable hosting. The heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' indicates a link farm designed for SEO manipulation, likely to obscure the true destination. The ML classifier strongly flags this PDF as malicious, suggesting it's part of a campaign to distribute malware or phishing content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9905

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 https://synerhu.ru/uplcv?utm_term=g+keyboard+apk+download
    • https://berbagiangka.com/contents/files/965079853.pdf
    • http://laptopplus.be/app/webroot/files/userfiles/files/josepovebuxibaluxu.pdf
    • https://www.scmsgroup.org/ckfinder/userfiles/files/donojikarozerutisow.pdf
    • https://yasacompany.com/upload/files/22085126165.pdf
    • http://zonwering-nederland.nl/ckfinder/userfiles/files/29343460964.pdf
    • http://h-st.nl/bestanden/files/lopuli.pdf
    • https://forkidsvietnam.vn/wp-content/plugins/super-forms/uploads/php/files/6uisp5081h72emm2km30rllh08/xenileduveru.pdf
    • http://yoshitomo-kokubunji.com/jcfiles/file/20994784868.pdf
    • http://www.sctiec.com/up_files/FCK/file/47412667647.pdf
    • https://bisnismedsos.com/userfiles/file/73424223088.pdf
    • https://www.hagensmarketing.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613593bac11e4---dawarosupoxiwawotusozalak.pdf
    • http://qiangka.com/ckfinder/userfiles/files/49615521490.pdf
    • http://imcborivali.org/userfiles/file/buvalaxibed.pdf
    • http://quangcaosmsgiare.com/media/ftp/file/tifupetagetazakikal.pdf
    • http://www.orarestauratorisaf.it/wp-content/plugins/formcraft/file-upload/server/content/files/1612f42b082fcb---gobununizorakukur.pdf
    • http://uts.edu.co/portal/app/ckfinder/userfiles/files/1478540624.pdf
    • http://ambulatorioveterinarioilprato.eu/userfiles/files/73403959097.pdf
    • http://creaorganization.com/depo/sayfaresim/file/42823736669.pdf
    • http://erkerlaender.de/wp-content/plugins/formcraft/file-upload/server/content/files/1613020e23f5e2---sisepematonolubozix.pdf
    • http://smartmedicaleg.com/wp-content/plugins/formcraft/file-upload/server/content/files/161315f9c92160---43916926107.pdf
    • http://timebymtm.com/upload/files/52304588102.pdf
    • http://abarappresentanze.it/userfiles/files/sawapafavog.pdf
    • http://execdentalclinic.com/uploads/ckfinder/userfiles/files/232234010.pdf
    • https://xosobacninh.vn/webroot/img/files/32412987732.pdf
    • http://tjsijiqing.com/ckfinder/userfiles/files/2021/0907/75c205de80c66ed0f4e4bb4978de967d.pdf
    • https://www.borzabadi.com/ckfinder/userfiles/files/tapitukomofutaxagab.pdf
    • http://dglytbt.com/upfolder/e/files/20210909130954.pdf
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000f34a.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xF34A 16792 bytes
font_01_sfnt_off00010b61.bin
2de18cd891fba824776a60c20860c07f416a4a2aa8ea4cc9646ea9da73b4eab3
pdf-font-stream PDF embedded font (sfnt) at offset 0x10B61 10496 bytes
font_02_sfnt_off00012330.bin
12e07049a7e15e3149b8ce24bdcb85a421d6d2813d04e879eba48b6edb82be07
pdf-font-stream PDF embedded font (sfnt) at offset 0x12330 18360 bytes