Malicious PDF — malware analysis report

Static analysis result for SHA-256 31a52e1a980f8f5f…

MALICIOUS

PDF

81.0 KB Created: 2021-08-21 11:04:20 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-24
MD5: e685a7acf7d7c2a32f74dcc14345d121 SHA-1: fd410a56c597374db03fecc7550c5ec1e39cfc25 SHA-256: 31a52e1a980f8f5ff990b535ca7c33736bb913e6531eea9d4372e7c14b251cd4
156 Risk Score

Malware Insights

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

The PDF file was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. It contains a link farm pointing to multiple compromised WordPress sites and disposable hosting, suggesting an attempt to distribute malicious content or phish users. The presence of numerous external URIs and the 'PDF_SEO_DISPOSABLE_LINK_FARM' heuristic indicate a deliberate effort to obscure the final malicious destination.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9960

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://agendaalzheimer.org/files/galeria/files/39300759442.pdf In PDF document text
    • https://aterhesseg.com/up_image/file/10730081483.pdfIn PDF document text
    • https://www.grandiosa.is/wp-content/plugins/super-forms/uploads/php/files/ulkd170c8pcsiti9uja8vdful6/bagepujimatelotexozuri.pdfIn PDF document text
    • http://movietek.vn/hinh-anh/files/sitid.pdfIn PDF document text
    • http://naphotelbangkok.com/userfiles/files/81738211337.pdfIn PDF document text
    • https://www.bistro-e.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607a6d8f115a2---52646851630.pdfIn PDF document text
    • http://www.predoisiasociatii.ro/wp-content/plugins/formcraft/file-upload/server/content/files/160944d1c91412---xabipivaberozi.pdfIn PDF document text
    • https://szud94.hu/img/sajatfile/files/74566404877.pdfIn PDF document text
    • http://younewstoday.com/task/userimages/file/gexirigepepazafiromajifod.pdfIn PDF document text
    • https://woodfur.in/userfiles/file/17933441986.pdfIn PDF document text
    • https://www.hed-endo.hr/wp-content/plugins/formcraft/file-upload/server/content/files/160e5aa51a0c94---99713589279.pdfIn PDF document text
    • http://www.centralperdana.com/file/lolozimene.pdfIn PDF document text
    • http://barcelonahotel.vn/UpLoadFile/file/tajubiguwelukusirinaxavir.pdfIn PDF document text
    • https://sidexsideaudio.com/wp-content/plugins/formcraft/file-upload/server/content/files/16090063e9a160---puxalulotifimapafe.pdfIn PDF document text
    • http://keemunblacktea.cn/uploads/file/030217163080.pdfIn PDF document text
    • http://ednak.com/wp-content/plugins/formcraft/file-upload/server/content/files/1610800d9c90f5---61973063699.pdfIn PDF document text
    • https://fanaf.com/article_ressources/file/76170346403.pdfIn PDF document text
    • https://www.clubmanizales.com.co/wp-content/plugins/formcraft/file-upload/server/content/files/160862032b5e75---32312258100.pdfIn PDF document text
    • https://totalyoumovement.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609a7c5e84ade---kerebotefivodagipogaki.pdfIn PDF document text
    • http://sherwoodchambergolf.com/ckfinder/userfiles/files/wirexag.pdfIn PDF document text
    • https://www.physioaktivkramer.de/wp-content/plugins/formcraft/file-upload/server/content/files/160813a84f045f---fopirarukugegivel.pdfIn PDF document text
    • http://cutskytools.com/d/files/21741081869.pdfIn PDF document text
    • http://jedwines.com/cmsCart//upload/file/muzalewuv.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/A3Ryygt5BCM/uplcv?utm_term=tucanes+de+tijuana+exitos+mfPDF 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_off0000d688.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD688 10784 bytes
SHA-256: 09b71b962a7a75ec30d1576964e41f587eb29c0e8a289280d009e9620e1483b1
font_01_sfnt_off0000ef61.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEF61 18200 bytes
SHA-256: e69b6c7bf1e8283244e76330b02f2b927e1a6ad1c7f6b5a3b4051187b1bd2699
font_02_sfnt_off00011d1e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11D1E 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1