Malicious PDF — malware analysis report

Static analysis result for SHA-256 99816a61e34ddba1…

MALICIOUS

PDF

81.4 KB Created: 2021-09-13 15:58:41 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: 610d5572cedfa67573d69401878b41b4 SHA-1: 2bd1b36ce145bbb5c9a1f0328581dcd3123152b0 SHA-256: 99816a61e34ddba1dd99112057c70a4e902f3e3c897d688ca941ec8021730f18
156 Risk Score

Malware Insights

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

The PDF contains numerous links to various domains, many of which are hosted on compromised CMS platforms or appear to be disposable for SEO purposes. The ML classifier and ClamAV detection strongly indicate malicious intent, likely phishing or malware distribution via these links. No scripts were extracted, and the document body was unreadable, so the attack pattern is inferred from the link farm heuristic and URL analysis.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9968

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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 https://dpengineerindia.com/admin/userfiles/file/8132176487.pdf In PDF document text
    • http://njxinbell.com/upload/files/dexujetudojefexisiguxabe.pdfIn PDF document text
    • https://funbugs.ie/files/file/xewima.pdfIn PDF document text
    • http://contelex.it/userfiles/files/56326758125.pdfIn PDF document text
    • http://rtm-plus.com/ckfinder/userfiles/files/8949542784.pdfIn PDF document text
    • http://jmvlpslimited.com/ci/userfiles/files/72147608917.pdfIn PDF document text
    • http://mwbright.com/upload_fck/file/2021-9-10/20210910235735473831.pdfIn PDF document text
    • http://gamax-moto.cz/data/dokumenty/47320174495.pdfIn PDF document text
    • https://jamuiboe.com/webroot/upload_media/piwinitereluze.pdfIn PDF document text
    • https://www.disbel.es/ckfinder/userfiles/files/ribunoburogugene.pdfIn PDF document text
    • https://marblobathware.ph/app/webroot/img/files/nurofujapatarupilovuveson.pdfIn PDF document text
    • http://heatexchangersolution.com/upload_fck/file/2021-9-5/20210905071250617542.pdfIn PDF document text
    • https://tortugafilms.ca/adminfiles/file/bafabibivujera.pdfIn PDF document text
    • https://skvely-kup.cz/files/file/xetoxat.pdfIn PDF document text
    • http://studioambienteterritorio.it/userfiles/files/47678507847.pdfIn PDF document text
    • http://ressourcengarten.de/azubi/userfiles/files/87526792510.pdfIn PDF document text
    • http://onroerendgoedindex.nl/images/uploads/wofifide.pdfIn PDF document text
    • http://mnarch.it/userfiles/files/fikaxujowizisijof.pdfIn PDF document text
    • http://galsabino.it/userfiles/files/95605124576.pdfIn PDF document text
    • https://sipsib.ru/wp-content/plugins/super-forms/uploads/php/files/a6e009975208d258e9178e3cebb406b1/20832695329.pdfIn PDF document text
    • https://nuevocoach.co.uk/wp-content/plugins/super-forms/uploads/php/files/8d9f2799b7e6f6c7be50e6193371c009/silaj.pdfIn PDF document text
    • http://www.festivalmarrakech.info/wp-content/plugins/formcraft/file-upload/server/content/files/16139a2c4b35fb---jilazusoronekap.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/fzgW7-mxBc0/uplcv?utm_term=bloons+tower+defense+2+unblockedPDF 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_off0000cf3a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCF3A 10808 bytes
SHA-256: dd27922ea9f1e6eb24f3361762d7796433237d9de83c5e303040eab22ee88204
font_01_sfnt_off0000e875.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE875 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00010087.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10087 21324 bytes
SHA-256: 14b84c82dc06bc0b1346ec52c0a56b834bc7c945112ffa93088031bc1cfdd3bb