Malicious PDF — malware analysis report

Static analysis result for SHA-256 10cb7f3e8c628354…

MALICIOUS

PDF

86.5 KB Created: 2021-07-04 06:20:31 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-08-20
MD5: 0e6872b50e8b8d244c184c0ad1b0d050 SHA-1: e818ee7437536bfc3204b8736a4cbac90d920e9f SHA-256: 10cb7f3e8c628354d5956439276f70086a9152710038d16bd60ec45df61a80da
204 Risk Score

Malware Insights

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

The sample was flagged by ML classifiers and ClamAV as malicious, with specific heuristics indicating it's a link farm pointing to compromised CMS uploads and a fake CAPTCHA lure. The presence of embedded URLs and the nature of the heuristics suggest the document is designed to trick the user into downloading a secondary payload, likely by presenting a fake verification prompt. No scripts were extracted, but the overall pattern points to a phishing or social engineering attack.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9970

Heuristics 8

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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.
  • 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 https://www.vibrationmonitoring.asia/wp-content/plugins/formcraft/file-upload/server/content/files/1607dcac1b1c49---nopolokumijitaw.pdf In PDF document text
    • http://beachfirebrands.com/userfiles/file/17268432014.pdfIn PDF document text
    • https://ecomassage.pt/wp-content/plugins/super-forms/uploads/php/files/aqc7a08fid0vhh34kfomg76jbd/26023139943.pdfIn PDF document text
    • https://ccveg.org/wp-content/plugins/super-forms/uploads/php/files/ogdf8iqc7moq3r2grirkec9dr4/buwegadokagajuluda.pdfIn PDF document text
    • http://es-umzuege-transporte.de/wp-content/plugins/super-forms/uploads/php/files/12797ff30869cd750590e6ac81d4b2c2/tigonilalezamozaw.pdfIn PDF document text
    • http://minhnguyenvn.com/uploads/userfiles/file/gover.pdfIn PDF document text
    • http://yatros.ro/wp-content/plugins/formcraft/file-upload/server/content/files/160bcdc93438f2---vifozusitufuna.pdfIn PDF document text
    • https://dangeloremodeling.com/nbloom/fckuploads/file/46340199215.pdfIn PDF document text
    • https://mmszke.hu/files/file/sewulap.pdfIn PDF document text
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/160cb7c6fe51f2---piruminujimamazamaxigi.pdfIn PDF document text
    • http://discarga.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c1c9915b8ee---29587684751.pdfIn PDF document text
    • http://aliancegroup.su/wp-content/plugins/formcraft/file-upload/server/content/files/160a9c223bf5a3---6436316027.pdfIn PDF document text
    • http://lakehighlandsrw.org/clients/863582/File/mufenaxabonepumodi.pdfIn PDF document text
    • https://www.sir.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/160c15bb9d1b18---degoxela.pdfIn PDF document text
    • https://www.capitalroofingct.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609b45788dcae---somenaros.pdfIn PDF document text
    • https://dm288.com/slicice/file/deretulufumamijedaxuxemid.pdfIn PDF document text
    • https://heykidsletscook.info/wp-content/plugins/super-forms/uploads/php/files/b9b65d0622353bc3f467c46f34883ea3/rivitunawa.pdfIn PDF document text
    • https://happycustomerservice.com/wp-content/plugins/super-forms/uploads/php/files/494c10d11105ab193b2d54187384f413/26989497682.pdfIn PDF document text
    • http://ankurgroups.com/userfiles/file/kuripiwukowiji.pdfIn PDF document text
    • http://www.nbrownies.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160ba980da048d---59653617932.pdfIn PDF document text
    • http://dush-kz.ru/uploads/fck/file/lolibuwugosu.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/A3Ryygt5BCM/uplcv?utm_term=how+to+hack+to+get+robux+2020PDF 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_off0000efb0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEFB0 10852 bytes
SHA-256: 4c452194204d4e494ee20d3a6d7de91772861b7c5d807a34a9bdf2bbd9601fc6
font_01_sfnt_off0001090e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1090E 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00012120.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12120 17052 bytes
SHA-256: 25abd4a76cc419dc8f23bbb44631748620b6036e12fb7e5e9efea69e435e337d

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