Malicious PDF — malware analysis report

Static analysis result for SHA-256 b4a93decbbe11e58…

MALICIOUS

PDF

81.7 KB Created: 2021-09-22 23:33:28 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-02
MD5: 42d3696b9a782eb96f481bf714c9709c SHA-1: bb9fec2b6d5f4c913d8c01df6bd3cea08e35410f SHA-256: b4a93decbbe11e58c35343dc8f87fb25cb8ec720091a03f29258944f88a787d5
86 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs pointing to a link farm, as indicated by the PDF_SEO_DISPOSABLE_LINK_FARM heuristic. The ML classifier also flagged the PDF as malicious with high confidence. The document body is heavily obfuscated, preventing a clear understanding of its specific lure, but the overall structure suggests a malicious intent to redirect users to potentially harmful content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9987

Heuristics 5

  • 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.
  • QR-code redirect lure medium SE_QR_LURE
    Document instructs the user to scan a QR code with a phone — consistent with QR phishing, but also common in legitimate documents
  • 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://jyjwqj.com/uploadfile/file///2021091004594160.pdf In PDF document text
    • http://synergyproperty.com/images/files/60282148848.pdfIn PDF document text
    • http://formpart.com/upload/ckfinder/files/68748351815.pdfIn PDF document text
    • http://samtle.net/ckupload/files/dogoxif.pdfIn PDF document text
    • http://smeeing.com/userfiles/files/bopegavi.pdfIn PDF document text
    • https://listapp.in/ci/userfiles/files/nuluwuwabolekifeb.pdfIn PDF document text
    • http://marktoby.com/akram/know_news/admin/userfiles/file/66112039581.pdfIn PDF document text
    • http://ozt.zielonetarasy-cieplice.pl/uploads/userfiles/files/nedat.pdfIn PDF document text
    • https://art-eria.pl/mandarynka/pliki/files/21488719772.pdfIn PDF document text
    • http://kcwoman.medsoft.kr/pds/userfiles/files/56921266586.pdfIn PDF document text
    • http://ipvoicenj.com/wp-content/plugins/formcraft/file-upload/server/content/files/16134935346eed---88965656859.pdfIn PDF document text
    • https://trungtamgiasuhcmmq.com/uplaod/quangtri/files/90122876777.pdfIn PDF document text
    • http://www.mostenpo.jp/userfiles/files/nodig.pdfIn PDF document text
    • http://china-baby-clothes.com/d/files/78432680910.pdfIn PDF document text
    • http://tmacfashion.com/ckfinder/userfiles/files/lomagijatiwiguwotu.pdfIn PDF document text
    • https://akonis.ch/userfiles/files/77365254837.pdfIn PDF document text
    • https://agros.net/uploads/file/89764880150.pdfIn PDF document text
    • https://armour-technoz-ca.otzol.net/ckfinder/userfiles/files/kopawominajosalimawow.pdfIn PDF document text
    • http://phuocthuan.vn/images/pic/file/64138294991.pdfIn PDF document text
    • http://yaqeen-eg.com/userfiles/file/lefonebafaxefoximizaku.pdfIn PDF document text
    • http://www.guus.edu.mn/ckfinder/userfiles/files/54926885186.pdfIn PDF document text
    • http://clinicaveterinariagussago.com/userfiles/files/topijofabafizex.pdfIn PDF document text
    • http://nationalherbo.com/userfiles/file/79959916596.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/1xuhb7AK25c/uplcv?utm_term=calligraphy+generator+copy+pastePDF 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_off0000d76a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD76A 18812 bytes
SHA-256: ebae69ca487b292a8f9fd6714188a973173e2be8aae66ca35d035f623f8f6214
font_01_sfnt_off00010911.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10911 10796 bytes
SHA-256: 74d16b97606599fb54df43fc3156281f64c8be0ea7becb7ef3adda72f7e2d14b
font_02_sfnt_off000121f4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x121F4 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1