Malicious PDF — malware analysis report

Static analysis result for SHA-256 a6acb481e758d031…

MALICIOUS

PDF

71.2 KB Created: 2021-09-22 18:17:38 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: dfa367cc8ee94870caebf5e6ed68e6fc SHA-1: 83394c91bd0657caf319cfe8d5f556dee146bd3d SHA-256: a6acb481e758d031a739d07f2d2cf17dc6848861267466df69c73ae0615f9cd4
86 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The ML classifier strongly indicates this PDF is malicious, and heuristic firings confirm malformed streams indicative of exploits. The document contains numerous embedded URLs, many pointing to potentially malicious domains, suggesting an attempt to redirect the user to a compromised site or download further malware. The presence of a link farm on disposable hosting further supports a malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

Heuristics 5

  • 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://doluhosting.com/calisma2/files/uploads/tuwokiroribotazuxitigixop.pdf In PDF document text
    • https://www.hippocratio.gr/ckfinder/userfiles/files/labizubusasukiti.pdfIn PDF document text
    • https://karlholmbygg.se/UserFiles/files/36934803707.pdfIn PDF document text
    • http://www.forteks.com.br/admin/ckeditor/ckfinder/userfiles/Images/73035573101.pdfIn PDF document text
    • http://bluestandard.pl/ckfinder/userfiles/files/xikukepomaturixojuwokib.pdfIn PDF document text
    • http://www.saito-ken.jp/userdata/file/luman.pdfIn PDF document text
    • http://ruben.pl/ckfinder/userfiles/files/mekirobabagiz.pdfIn PDF document text
    • https://digireg.se/upload/93822398686.pdfIn PDF document text
    • http://audiomaster.se/wp-content/plugins/formcraft/file-upload/server/content/files/161369c6d3c37e---81200433313.pdfIn PDF document text
    • http://thibangoto.com/app/webroot/uploads/files/konev.pdfIn PDF document text
    • http://shoreluxurylimos.com/userfiles/files/55610703006.pdfIn PDF document text
    • https://cam-ceeds.org/ckfinder/userfiles/files/puripef.pdfIn PDF document text
    • http://www.sas.edu.mn/ckfinder/userfiles/files/77126341241.pdfIn PDF document text
    • http://kuhomania.ru/ckfinder/userfiles/files/wedatirawux.pdfIn PDF document text
    • http://xn--80aab8aioy.xn--p1ai/userfiles/file/841550289.pdfIn PDF document text
    • https://motoquadro.de/userfiles/file/dasunisererelevuvenikek.pdfIn PDF document text
    • http://codienlanhminhquang.com/upload/files/kefirugotojetat.pdfIn PDF document text
    • http://www.companyforte.com/imagenes/editor/file/nedewamutuzugofibir.pdfIn PDF document text
    • http://stamforgtechnologies.com/uploads/difovosasabebuxaj.pdfIn PDF document text
    • http://sungsam.net/userData/board/file/75590051341.pdfIn PDF document text
    • https://iphone-odklep.si/vsebina/tuvekexobosizawosuwuvaw.pdfIn PDF document text
    • https://eko-briketes.lv/userfiles/files/30906850468.pdfIn PDF document text
    • https://pabausa.org/wp-content/plugins/formcraft/file-upload/server/content/files/16137e34772cd6---99722546318.pdfIn PDF document text
    • https://canionglobal.com/FCKeditor/file/45949824961.pdfIn PDF document text
    • https://automatisme-portail-bordazzi.fr/userfiles/fichiers/51286290086.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/ngfLrbzwjls/uplcv?utm_term=wattpad+old+version+download+linkPDF 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_off0000b8d0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB8D0 10620 bytes
SHA-256: a95b68f7a96ad7dc0eeefece329aff532db1f51d301a0202e04a5c50392af180
font_01_sfnt_off0000d13f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD13F 14804 bytes
SHA-256: 5485b3d1d6ff5a89ce2d0869096d92a640aac968447a3c8f8fe5b5266ccdeb70
font_02_sfnt_off0000f6a8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF6A8 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1