Malicious PDF — malware analysis report

Static analysis result for SHA-256 3d76430ce98dd396…

MALICIOUS

PDF

83.3 KB Created: 2021-09-15 20:55:48 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: 95fbccdfd8ea4f6acd5ad5813fbae2c2 SHA-1: b4e4672d69da0e2a7a2aa5e0ef0460e58e19fbe8 SHA-256: 3d76430ce98dd396f87a7b5f53386fe8f890c23c3b420249b40707d8259fbb8d
152 Risk Score

Malware Insights

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

The PDF contains embedded JavaScript and presents a fake CAPTCHA, indicating an attempt to trick the user into executing malicious code or downloading a payload. The presence of numerous external links, some pointing to compromised WordPress uploads, further supports a malicious intent, likely to serve as a lure for further compromise. The ML classifier strongly flagged this PDF as malicious.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

Heuristics 8

  • Fake CAPTCHA / human verification prompt high SE_FAKE_CAPTCHA
    Document displays a fake CAPTCHA or human-verification prompt — used to trick users into running commands or pressing keyboard shortcuts
  • 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • Visual download / call-to-action button lure low SE_DOWNLOAD_BUTTON
    Document contains a call-to-action phrase ('Click here to download', 'Download Now', etc.) — low-signal unless other findings point to a malicious workflow
  • 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://pro-customer.de/userfiles/file/66383034079.pdf In PDF document text
    • https://hoangvan.vn/wp-content/uploads/files/wuvixujagewijotatika.pdfIn PDF document text
    • http://jungam21.com/upfiles/file/1631526922.pdfIn PDF document text
    • https://controlcert.se/wp-content/plugins/formcraft/file-upload/server/content/files/1613996529d52d---90844618334.pdfIn PDF document text
    • http://galettedesrois.eu/userfiles/file/27065362173.pdfIn PDF document text
    • https://gencatakan.com/upload/file/nejoda.pdfIn PDF document text
    • https://underworldgear.com/admin/images/fckImg/file/doreriwupizi.pdfIn PDF document text
    • http://machinesupplier.cn/data/product/file/2021910_111523_151.pdfIn PDF document text
    • http://northmarking.com/userfiles/files/23317654061.pdfIn PDF document text
    • http://elmiraclassiccountry.com/wp-content/plugins/super-forms/uploads/php/files/8d8a3d71a1dd0ff0a3ef896caa9af2eb/3388309314.pdfIn PDF document text
    • http://sk-massimo.com/js/upload/files/risugotuzeroxobubozonej.pdfIn PDF document text
    • http://carrasvilla.es/uploads/files/negiwubezifovudadijutezo.pdfIn PDF document text
    • http://aotwresort.info/ckfinder/userfiles/files/fadatejiz.pdfIn PDF document text
    • http://jeyadhurgatemple.com/userfiles/file/zarasipologoxanapigenugu.pdfIn PDF document text
    • https://thesmithgrouphouston.com/wp-content/plugins/super-forms/uploads/php/files/34d0a58d2acaa4c968faf98619ba859e/wotekosubopo.pdfIn PDF document text
    • https://vakukh.ru/wp-content/plugins/super-forms/uploads/php/files/850d01368fced605d02fde099757cd23/57615801986.pdfIn PDF document text
    • https://sharkovinkom.com/sharkovinkom.com/ckfinder/userfiles/files/tuvakelupisemebaw.pdfIn PDF document text
    • http://anhuizpyy.com/upload_fck/file/2021-9-8/20210908024725510131.pdfIn PDF document text
    • http://konsultacjenaukowe.eu/Upload/file/42946450934.pdfIn PDF document text
    • http://etkenkalip.com/files/falagunazani.pdfIn PDF document text
    • https://robertmatzuzi-massagetherapist.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/161348b39719e0---43571643269.pdfIn PDF document text
    • http://julieesteban.com/wp-content/plugins/formcraft/file-upload/server/content/files/16136ced10b0e3---javolewo.pdfIn PDF document text
    • http://rakkhunnursinghome.com/user_img/files/69796935571.pdfIn PDF document text
    • http://probeg2000.ru/files/userfiles/files/15030009191.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/fzgW7-mxBc0/uplcv?utm_term=attack+on+titan+2+final+battle+android+apkPDF 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_off0000e068.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE068 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000f87a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF87A 17616 bytes
SHA-256: ad40734059a63eb8ec7f1dfced313b66344f891ddf9c671633a58aea4fe51f8c
font_02_sfnt_off00012624.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12624 10780 bytes
SHA-256: 8f9041a24791c8ed730429d31af09aa982b67729a2baf07fc3a1613efb437d73

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