Malicious PDF — malware analysis report

Static analysis result for SHA-256 4b53d91fba18dfa1…

MALICIOUS

PDF

84.5 KB Created: 2021-09-06 12:08:58 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: 34300a2448563711f32df9a6989e4cc1 SHA-1: af44db13698e3053a412b4b04b78273bcddeb6d1 SHA-256: 4b53d91fba18dfa1287ee6a9c640e043c75b578ef71722a4a1452df69173fe0f
196 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

This PDF document was flagged by a machine learning classifier and ClamAV as malicious, specifically as a phishing trojan. The heuristics indicate it functions as a link farm, directing users to various compromised or disposable hosting sites, and employs a 'password-protected archive lure' to conceal its payload. While no scripts were directly extracted, the PDF structure and embedded links suggest an attempt to trick users into downloading and then opening a password-protected file, likely containing a secondary malicious payload.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9964

Heuristics 7

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • Password-protected archive handoff high SE_PASSWORD_ARCHIVE_LURE
    Document gives password instructions for an archive or attachment — often used to keep payloads encrypted until after gateway scanning
  • 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://www.isgs.org/wp-content/plugins/super-forms/uploads/php/files/efbdb78791ac77b1b7919a6be4a9ec9f/salokamikesuwivare.pdf In PDF document text
    • https://lixtech.com.tw/ckfinder/ckfiles/files/pefufado.pdfIn PDF document text
    • https://autohausnschmidt.de/userfiles/file/fobodifezuzokunadeb.pdfIn PDF document text
    • https://www.a2zmedical.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/160a8bcd0eac63---jadolako.pdfIn PDF document text
    • http://chayka-svg.ru/files/46783151919.pdfIn PDF document text
    • https://luminex.pl/upload/file/jusaxujebopixadefutuvip.pdfIn PDF document text
    • https://drahmetbostanci.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606d030deadc7---18477250134.pdfIn PDF document text
    • http://stavbyhes.cz/ckfinder/userfiles/files/72098960989.pdfIn PDF document text
    • http://ovartec.com/wp-content/plugins/formcraft/file-upload/server/content/files/16076041856a99---64570462138.pdfIn PDF document text
    • http://nek.ua/wp-content/plugins/formcraft/file-upload/server/content/files/16077b471b7047---26584034038.pdfIn PDF document text
    • https://wentworthre.com/wp-content/plugins/super-forms/uploads/php/files/3a2896b881ed0b4d07d011bb1709de0a/54626380696.pdfIn PDF document text
    • http://svenstavik.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a76a08a0ede---17458533070.pdfIn PDF document text
    • http://solemarservizi.it/userfiles/files/48103129475.pdfIn PDF document text
    • https://g-ortho.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160831746e3b63---71812234466.pdfIn PDF document text
    • http://novaserv.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607839527581c---roregoverolapezijifumofu.pdfIn PDF document text
    • http://global-gypsum.com/wp-content/plugins/formcraft/file-upload/server/content/files/160d54dc65f021---1519814984.pdfIn PDF document text
    • https://sjalikave.hu/pictures/file/fafutowufubefopepe.pdfIn PDF document text
    • http://www.expo-hotel.com/english/wp-content/plugins/formcraft/file-upload/server/content/files/16078a6f4cd7e4---kojujuzujuduj.pdfIn PDF document text
    • https://englewoodgrassfarm.com/wp-content/plugins/super-forms/uploads/php/files/bfccefc50f093e30efd4dacdd44ff354/dajadunefujaki.pdfIn PDF document text
    • http://maimungkorn.com/UserFiles/file/vemixi.pdfIn PDF document text
    • https://at-studio.tw/app/webroot/userfiles/files/20210811_222328.pdfIn PDF document text
    • https://lhorizon.ca/uploadHorizon/file/paxaganipumexezofomazis.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/6naE_Nh8_CY/uplcv?utm_term=textbook+of+mood+disorders+pdfPDF 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_off0000e44f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE44F 10644 bytes
SHA-256: 318e9580219b03edd6a6399cbef2e2151da9d339da4029092964c9b2166d0c56
font_01_sfnt_off0000fc81.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFC81 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00011493.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11493 18940 bytes
SHA-256: f2f79f80dc40cf8ea75ccb88c81b4d0cd23c2f09c7f13c40b9268a7ed0b78232

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