Malicious PDF — malware analysis report

Static analysis result for SHA-256 1667ad551af1eeed…

MALICIOUS

PDF

80.0 KB Created: 2021-09-11 18:31:14 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: c97c904d6c527477e7753ccc7d8ca582 SHA-1: 27969bcc5a65f455d8a1cea04c07c57d00ad0a98 SHA-256: 1667ad551af1eeedeaceaf74a142c7a17a1fdcdea821353ce6f8a330b3af3adb
146 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. Heuristics indicate malformed streams and a link farm structure, suggesting it's designed to redirect users to external, potentially malicious sites. The presence of embedded URLs and the PDF structure point towards a phishing or malware distribution campaign, likely initiated via spearphishing.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

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
  • Malformed active-content stream length medium PDF_MALFORMED_EXPLOIT_STREAM_LENGTH
    A PDF stream that carries active/exploit-looking content has a declared /Length that does not match the recovered stream body. Malformed stream boundaries and length mismatches are common parser-evasion/supporting evidence around Reader exploit streams.
  • 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://garglob.ru/uplcv?utm_term=korean+web+series+app PDF link annotation
    • http://ricarda-allegra.de/userfiles/file/68060302552.pdfIn PDF document text
    • http://www.injamal.es/nueva/ckfinder/userfiles/files/kuwiwafes.pdfIn PDF document text
    • https://kawanmto.net/contents/files/80320522576.pdfIn PDF document text
    • http://stihoplet.by/upload/editor/files/tibukonekewatamonado.pdfIn PDF document text
    • http://alexlunacoach.com/img/editor/file/godarivasafojugaropozudog.pdfIn PDF document text
    • https://simpangkanan.com/contents/files/niboraxifoximo.pdfIn PDF document text
    • https://isosklo.cz/uploads/fipurefilobukugisijisi.pdfIn PDF document text
    • https://v-rshine.com/upload/images/files/kozunoj.pdfIn PDF document text
    • https://asi-filter.pl/files/file/guzavep.pdfIn PDF document text
    • http://josquin-capella.de/download/12499386646.pdfIn PDF document text
    • https://cancelaria.pl/galeria/file/rapofemofixinigigino.pdfIn PDF document text
    • http://087334211.kad.tw/kads/ckfinder/userfiles/files/vikugivozagodusa.pdfIn PDF document text
    • https://soechi.net/userfiles/file/34573135257.pdfIn PDF document text
    • https://msiutilities.net/documents/pinuzivufuwitojimelotefa.pdfIn PDF document text
    • http://recviem.ru/img/upload/72529374208.pdfIn PDF document text
    • https://member-amz-seller-system.de/wp-content/plugins/super-forms/uploads/php/files/49ce6da27d8538bcceb26ac85a3ca00d/96256455163.pdfIn PDF document text
    • http://lemma-studio.pl/userfiles/file/2351821123.pdfIn PDF document text
    • http://ruben.pl/ckfinder/userfiles/files/93088650256.pdfIn PDF document text
    • https://printsolutions.ro/uploads/wysiwyg/files/gofigezezubojinepiv.pdfIn PDF document text
    • http://xmzhj.com/UserFiles/file/nadixinilerakizev.pdfIn PDF document text
    • https://nileagriculturalindustries.com/file/31669591285.pdfIn PDF document text
    • http://bafiti.com/sklep/userfiles/file/69479494359.pdfIn PDF document text
    • https://kayakbranson.com/wp-content/plugins/formcraft/file-upload/server/content/files/161312f477e960---66673047572.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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000d77e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD77E 16872 bytes
SHA-256: dcd30e5be06965142f78f6fd68be3911831fde992ddb55bae4754d2ac9cd2a32
font_01_sfnt_off00010309.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10309 10316 bytes
SHA-256: ca7e00b6852caf94a7456b17a1f0337674d2a15492fa6e223eb23fbc9d918a2f
font_02_sfnt_off00011a3d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11A3D 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1