Malicious PDF — malware analysis report

Static analysis result for SHA-256 a51fa159df50cee9…

MALICIOUS

PDF

81.0 KB Created: 2021-09-21 07:11:22 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: 7504a8239be735199b58a8136a941a03 SHA-1: 2472c13fd84519a468f58a8b14e13578e5ac4377 SHA-256: a51fa159df50cee9de1e8ea8af358b97bb7df22181526afd192f72bafa553b63
126 Risk Score

Malware Insights

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

The sample is identified as malicious by ML classifiers and ClamAV, indicating a high likelihood of malicious intent. The PDF utilizes a link farm strategy with numerous embedded URLs pointing to disposable hosting, suggesting an attempt to distribute further malicious content or phish users. The heuristic PDF_SEO_DISPOSABLE_LINK_FARM specifically flags this behavior.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9955

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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 http://phongkhamthienhoa.vn/images/files/gufofarexajupafav.pdf In PDF document text
    • https://nationalshield-uae.com/userfiles/files/79307618606.pdfIn PDF document text
    • https://beautydent.hu/editor_up/fiwurakorowipi.pdfIn PDF document text
    • http://ottotech.center/userfiles/file/60986902079.pdfIn PDF document text
    • http://an-professional.ru/img/files/file/98287203003.pdfIn PDF document text
    • https://hongmao.tw/uploads/files/202109190318408549.pdfIn PDF document text
    • http://vrieshorst.nl/images/uploads/file/89978276153.pdfIn PDF document text
    • http://jan-fotografie.nl/upload/files/23477360422.pdfIn PDF document text
    • https://ekinyalitim.com/depo/sayfaresim/file/6098592798.pdfIn PDF document text
    • http://enidental.com/userfiles/file/20210918042703.pdfIn PDF document text
    • http://donghozibistore.com/luutru/files/xirenexopasoxerako.pdfIn PDF document text
    • http://lawngo.net/fckfiles/gomajuwitekivomifuw.pdfIn PDF document text
    • http://proficlim.ru/public/userfiles/file/41206519913.pdfIn PDF document text
    • http://szjglaw.com/uploadfile/file/2021091804170873499.pdfIn PDF document text
    • http://texmet.pl/userimages/file/demaxuzulula.pdfIn PDF document text
    • http://montesantangelo.it/files/files/9736982905.pdfIn PDF document text
    • https://dampinggame.com/calisma2/files/uploads/giwazitawatatokesuw.pdfIn PDF document text
    • http://tianlanlawyer.com/filespath/files/20210912122920.pdfIn PDF document text
    • https://timminsrenovations.ca/file/IVIgUiW876b1hUIQ.pdfIn PDF document text
    • http://aesg2edcv.handylover.com/upload/files/wepunupuwuzap.pdfIn PDF document text
    • http://samtle.net/ckupload/files/deluxagugivufejumivakopol.pdfIn PDF document text
    • http://massvt.sk/editor_uploads/system/files/kepejab.pdfIn PDF document text
    • https://www.lumisolar.pe/wp-content/plugins/formcraft/file-upload/server/content/files/16135ac19487d8---78192935722.pdfIn PDF document text
    • https://autotrilogy.com/wp-content/plugins/super-forms/uploads/php/files/f4010ebdaa9d503e68a0d4e735400d7e/29222872267.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/Om9ozkHLxGw/uplcv?utm_term=warm+zone+mod+apkPDF 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_off0000daf6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDAF6 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000f30d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF30D 10292 bytes
SHA-256: 417e8d3d33bcd24c876c56fb2c5a725cec0f9620be8e7426e5e3a43a05dbc697
font_02_sfnt_off00010a33.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10A33 17376 bytes
SHA-256: 6d9cb06993b77d08b34bb31e2aa610cdb0d95086d56d0d2e127fa475c6bae4a1