Malicious PDF — malware analysis report

Static analysis result for SHA-256 18b9aca72d37165a…

MALICIOUS

PDF

82.0 KB Created: 2021-09-23 23:44:11 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 5be6b20457bbe05a3c43c5764f875eda SHA-1: c8d4d825c40464b97ef513492639d2302452df3d SHA-256: 18b9aca72d37165a6662692db9aaaa2eec0a9f1be84eb2e54798cbafcd1c01e2
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous external links, with one heuristic specifically identifying it as a link farm on disposable hosting. ClamAV and an ML classifier flagged the PDF as malicious, with the ML model outputting a high probability of maliciousness. The presence of embedded URLs and the overall structure suggest a phishing or malware distribution attempt, likely initiated via spearphishing attachment.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9981

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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 https://pt2-turbo-j3t.com/contents/files/78456395372.pdf
    • http://rund.cz/UserFiles/File/zokusunabi.pdf
    • https://thehouseconcert.com/ckfinder/userfiles/files/55082298200.pdf
    • https://spbmworld.com/anaeter_capital/siteadmin/userfiles/files/71457114008.pdf
    • http://studioboscono.it/userfiles/files/zolazasimosebidevowagaz.pdf
    • http://manvilastrust-org.bvirani.com/ckfinder/userfiles/files/6189097456.pdf
    • http://diskacme.dk/images/upload/file/mutifumutedupuki.pdf
    • https://karaari.leaddeehub.com/userfiles/files/91010145702.pdf
    • http://zvaracskaskola.eu/editor_uploads/system/files/1272127582.pdf
    • http://ikra-ekb.ru/files/fckeditor/file/tibolo.pdf
    • http://terredellamagnagrecia.com/userfiles/files/80085764115.pdf
    • http://versobrokers.eu/userfiles/files/75706289739.pdf
    • https://expobar.vn/app/webroot/files/images/pages/files/87295268120.pdf
    • http://elazentrale.de/images/uploaded/file/25987539006.pdf
    • https://coastalstudio.com/images/main/file/61771476653.pdf
    • http://productinfo.in/konadnew/userfiles/file/xovofak.pdf
    • https://adikkedua.com/contents/files/61745258794.pdf
    • http://hanilkwanla.com/uploads/files/2964857039.pdf
    • http://tythb.cn/uploadfile/files/jojagemifodu.pdf
    • http://ozhelalikram.de/resimler/files/82550202763.pdf
    • https://nguyenthelong.net/userfiles/files/48491029112.pdf
    • https://shiksha24.com/userfiles/files/sawibinipiwopuje.pdf
    • https://feedproxy.google.com/~r/skout/mBVl/~3/BvfzZFkJO3s/uplcv?utm_term=san+andreas+mobile+apk
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000dc7f.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xDC7F 16792 bytes
font_01_sfnt_off0000f491.bin
07848b789d32664742b6a582eb6ee9d2b65de52d283a3847ddbe34d94cf07d7a
pdf-font-stream PDF embedded font (sfnt) at offset 0xF491 17668 bytes
font_02_sfnt_off000121e0.bin
d17f0a0ca06241dc5f539cb2d0d61a9f8169e31e9e3d8d445488328ff5c2fcd0
pdf-font-stream PDF embedded font (sfnt) at offset 0x121E0 10764 bytes