Malicious PDF — malware analysis report

Static analysis result for SHA-256 31b905e8066c1679…

MALICIOUS

PDF

89.0 KB Created: 2021-08-07 02:14:36 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-07
MD5: 5c2aeaa4e6a3f13e09e82215435d9743 SHA-1: 2b344448c2ab3537193c60d04858af4b477e2c65 SHA-256: 31b905e8066c167948d44dbf40585af3f2f946a0bf3343e802c9202eee180120
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF contains multiple links pointing to compromised WordPress sites, specifically within the formcraft plugin's file upload directory. These links are designed to host and distribute further malicious content, as indicated by the 'PDF_SEO_DISPOSABLE_LINK_FARM' and 'PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM' heuristics. The ML classifier and ClamAV detection strongly suggest malicious intent, likely phishing or malware distribution.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9996

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 https://ventana-sur.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607cd8a2621c2.pdf In PDF document text
    • http://eduomania.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609c37dbc357f---14768658261.pdfIn PDF document text
    • http://allnatureint.com/userfiles/file/61689525834.pdfIn PDF document text
    • http://pantryscan.com/123cars/imagefck/file/50556568676.pdfIn PDF document text
    • http://constructionone.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1606c6bd6baad5---lemigedenajisowa.pdfIn PDF document text
    • http://csptech.net/admin/userfiles/file/rolisinozonomibisekedijis.pdfIn PDF document text
    • http://aedelsur.com/contenido/files/80526877397.pdfIn PDF document text
    • http://kimthienbao.com/userfiles/file/98325743449.pdfIn PDF document text
    • http://www.fliesen-brill.de/wp-content/plugins/formcraft/file-upload/server/content/files/16075333530e2a---66710113319.pdfIn PDF document text
    • https://www.lipfish.no/wp-content/plugins/formcraft/file-upload/server/content/files/1609ed37d4011d---57045242588.pdfIn PDF document text
    • https://avenirpourtous.fr/wp-content/plugins/formcraft/file-upload/server/content/files/160a8972e519f4---54347024114.pdfIn PDF document text
    • http://kraljicabih.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b9cc1b289d0---5489587691.pdfIn PDF document text
    • http://mindentudor.hu/userfiles/file/watirajanofiv.pdfIn PDF document text
    • https://lea-inc.com/wp-content/plugins/super-forms/uploads/php/files/1e168c12412d2e0365e6336224f1a234/4533397647.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/cv9VXjIrmdE/uplcv?utm_term=how+to+calculate+gpa+with+excelPDF link annotation
    • http://e1pl2.nazwa.pl/busy/fotki/file/wanatig.pdfIn PDF document text
    • 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 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000e993.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE993 3956 bytes
SHA-256: b252d7afd58d8a8134b98375d36b2d134a5b35839d730340b8131d3cb14a678a
font_01_sfnt_off0000f898.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF898 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off000110aa.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x110AA 17156 bytes
SHA-256: 2d9a8c8fa778a206bb3953799baad1f8e81ef3221cf1cee09a52fb65ed27efe7
font_03_sfnt_off00013daa.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13DAA 10560 bytes
SHA-256: f84964d08815b6f97714b7ca51c5e9a3d1b6093e198ba7fd1dd92ce813699fec