Malicious PDF — malware analysis report

Static analysis result for SHA-256 91afab71845d0328…

MALICIOUS

PDF

86.8 KB Created: 2021-08-04 02:07:04 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: 76171b9a521ab4ea9c0c581a83e010e0 SHA-1: 7a6a2958c91dc56d8cbdc05596c98d9afb70d895 SHA-256: 91afab71845d032865573cb136a015d9daa1ea2948f1fe7e2c089a73b64ce446
156 Risk Score

Malware Insights

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

The PDF contains a link farm pointing to numerous unknown URLs, many hosted on compromised CMS upload directories. ClamAV and ML classifiers identified this PDF as malicious, likely a phishing or malware distribution lure. The presence of multiple PDF link farm heuristics indicates a deliberate attempt to obscure the final destination and potentially evade detection.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9991

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://zhansq.cn/upload/file/18998266966.pdf In PDF document text
    • https://briljant-maleri.se/UserFiles/files/lovirelugunenozewin.pdfIn PDF document text
    • http://konemara.hu/userfiles/file/12556780366.pdfIn PDF document text
    • http://angelcabrera.com/FCKfiles/file/59528061187.pdfIn PDF document text
    • https://hoffmanowska.pl/wp-content/plugins/formcraft/file-upload/server/content/files/160904f503397f---xedibumovajokanizipupora.pdfIn PDF document text
    • http://bajcsidavidfoto.com/_user/file/33488918709.pdfIn PDF document text
    • https://paloaltospeakerseries.com/wp-content/plugins/super-forms/uploads/php/files/743f4de14302f90ab8929c2b4e1edaff/pulatonatuwiluxov.pdfIn PDF document text
    • https://www.numberoneporthill.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/1607f8b1422265---36326488725.pdfIn PDF document text
    • https://kvartira-zalog.ru/wp-content/plugins/super-forms/uploads/php/files/8d0ce1d34f4a7a78a1aa80aa34d2dde8/wavexal.pdfIn PDF document text
    • http://bitite.lv/media/txt/122/file/53772514703.pdfIn PDF document text
    • http://www.adarshvidhyasankul.org/userfilesfile/safawexozajuse.pdfIn PDF document text
    • https://etimes.mn/uploads/files/rijavuribo.pdfIn PDF document text
    • http://gabinetortodontyczny.eu/userfiles/file/mixupefesasofetutaxidat.pdfIn PDF document text
    • http://ibshop.gr/uploads/_uploads/files/nibekidepogejes.pdfIn PDF document text
    • https://hightechrustremovers.nl/wp-content/plugins/formcraft/file-upload/server/content/files/160a38e8a3f9ae---20024685129.pdfIn PDF document text
    • http://armanetti.com/images/dubiroj.pdfIn PDF document text
    • https://foodvellythailand.com/upload/files/2367080926.pdfIn PDF document text
    • http://anpo.vn/upload/files/63768230631.pdfIn PDF document text
    • https://www.kalirich.com/wp-content/plugins/super-forms/uploads/php/files/8dp3pfp0hc9eah12qp5ftfm3q2/36995051564.pdfIn PDF document text
    • http://fsoa.cn/userfiles/file/91910858893.pdfIn PDF document text
    • http://shahnawazonline.com/uploads/files/pawuvozan.pdfIn PDF document text
    • https://sk-developers.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609d1f0635d84---41779964914.pdfIn PDF document text
    • https://www.vibrationmonitoring.asia/wp-content/plugins/formcraft/file-upload/server/content/files/160a5eaa443ad0---2444700417.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/3vuEKuznOb8/uplcv?utm_term=c%C3%B3mo+se+puede+simplificar+fracciones+algebraicasPDF 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_off0000e909.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE909 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off00010120.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10120 11276 bytes
SHA-256: bec37254f0ae7e1ad1d029d13d8730b0e95f9bd2357fe082a8fd9371c08b9357
font_02_sfnt_off00011ad8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11AD8 18560 bytes
SHA-256: 324916dc46beeaf35319bb91d827638fbe8e2ae996c16ab096469918d49a1572

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