Malicious PDF — malware analysis report

Static analysis result for SHA-256 553bbf521e7476fa…

MALICIOUS

PDF

86.5 KB Created: 2021-09-03 04:12:10 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-07
MD5: a3ca990052abe91b2c543fa64f67c70f SHA-1: 421210ad8b136527f1a28d7a9d5ca73da7c24620 SHA-256: 553bbf521e7476fa63937995146fe61a7c90f823be0b9d3e38a27e96af76a600
156 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs, many of which point to compromised CMS upload directories or disposable hosting, indicating a link farm designed to redirect users. The ML classifier and ClamAV detection strongly suggest malicious intent, likely phishing or malware delivery. No scripts were extracted, but the structure and URL patterns are indicative of a malicious PDF.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9952

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://eastcoastbiker.de/sites/default/files/file/nunigedojakegesadiruji.pdf In PDF document text
    • http://www.cuadernos.in/wp-content/plugins/formcraft/file-upload/server/content/files/160a46b7aadc4c---nunoruseparaniz.pdfIn PDF document text
    • https://www.kadinlarsitesi.org/wp-content/plugins/formcraft/file-upload/server/content/files/160f514841ff01---zirejilel.pdfIn PDF document text
    • https://thehero88vip.com/ckfinder/images_store/files/betodov.pdfIn PDF document text
    • https://jaiminsales.com/ckfinder/userfiles/files/5611343163.pdfIn PDF document text
    • https://neavocats.com/wp-content/plugins/super-forms/uploads/php/files/9ca4c120bc77fc902e6d965599ce5da9/32751437663.pdfIn PDF document text
    • http://vdgairconditioning.nl/wp-content/plugins/formcraft/file-upload/server/content/files/16084e214a0777---58147027622.pdfIn PDF document text
    • http://vorne-sitzen.eu/pcms/content/file/3694035341.pdfIn PDF document text
    • https://treasurehunterdetectors.com/ckfinder/userfiles/files/70692112935.pdfIn PDF document text
    • https://sabagdasarov.ru/upload/file/pozezevik.pdfIn PDF document text
    • http://msslink.ru/userfiles/files/legubu.pdfIn PDF document text
    • https://www.kngroup.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608a5d1037c05---52766338647.pdfIn PDF document text
    • http://www.acefence.com/wp-content/plugins/formcraft/file-upload/server/content/files/160e4b0bfcba87---77781422080.pdfIn PDF document text
    • https://dacoma.ro/wp-content/plugins/formcraft/file-upload/server/content/files/16073cb4917338---riridikedesedo.pdfIn PDF document text
    • https://rybczewice.pl/userfiles/file/zozozubevefujilegadivumem.pdfIn PDF document text
    • https://adepotcustom.com/UploadFiles/file/20210524165424174.pdfIn PDF document text
    • http://sutinlawkrabi.com/ckfinder/userfiles/files/23796123378.pdfIn PDF document text
    • http://offerseir.com/basefile/offerseircom/files/66331403099.pdfIn PDF document text
    • http://chamdure.com/DATA/files/53092511242.pdfIn PDF document text
    • http://a-daily.jp/app/webroot/contents_img/files/fuxozas.pdfIn PDF document text
    • http://baodieptailor.com/uploads/2021-08-09/images/files/48565102048.pdfIn PDF document text
    • http://vlaamspatientenplatform.be/_plugin/ckfinder/userfiles/files/mapevudibu.pdfIn PDF document text
    • http://www.tomasjelinek.com/img/pub/file/supuxeripuzupurivoligon.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/GLLx1DTH0VQ/uplcv?utm_term=miscript+sybr+green+pcr+kit+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_off0000eb15.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEB15 18492 bytes
SHA-256: 96776e9c8d55749ba60518b09218cdbc15896f844064038ed449f901c2db1b17
font_01_sfnt_off00011b1c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11B1C 11036 bytes
SHA-256: 0dbd043489d1ee43676b77ff676fb0ed9bd03d55d3904aa2ae2dc7b0e9fdb59a
font_02_sfnt_off000134a0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x134A0 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1