Malicious PDF — malware analysis report

Static analysis result for SHA-256 21b9e0e6e05f8706…

MALICIOUS

PDF

91.6 KB Created: 2021-09-01 17:49:04 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-31
MD5: 4947162bca8853c7ffc82df0902468aa SHA-1: df0d3838a563ce087b6900ca25967691f1cc42ca SHA-256: 21b9e0e6e05f870642b76778785c393bee6b6be4abc356ea07166be79f8d3a1a
184 Risk Score

Malware Insights

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

This PDF file contains embedded JavaScript, which is a common technique for exploiting PDF vulnerabilities to execute arbitrary code. The heuristics indicate a malformed stream length and a link farm pointing to compromised CMS uploads, suggesting the PDF is designed to redirect users to malicious content or download further malware. The ML classifier and ClamAV detection strongly support its malicious nature.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9980

Heuristics 8

  • 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.
  • PDF link farm points to compromised-WordPress upload storage medium PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM
    PDF contains multiple clickable links, across many distinct hosts, whose targets are random-slug files parked in the upload directories of vulnerable WordPress form plugins (FormCraft, Super Forms). This is the hallmark of the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains hosted on compromised sites. The PDF itself carries no exploit — the risk is the linked destinations.
  • 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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://popa.com.br/wp-content/plugins/super-forms/uploads/php/files/9d5ffad02487f3ec9b8f0b67289b7732/8372217980.pdf In PDF document text
    • https://htchninc.com/d/files/87549774186.pdfIn PDF document text
    • https://yastudio.net/wp-content/plugins/super-forms/uploads/php/files/dce0f4d4baf070c8e6958e39e50f921b/torilorexo.pdfIn PDF document text
    • http://studiomanzella.com/userfiles/files/14907645832.pdfIn PDF document text
    • http://irvinenott.co.uk/ckfinder/userfiles/files/43738750452.pdfIn PDF document text
    • http://www.hydro-tg.pro/upload/file/wavimadefij.pdfIn PDF document text
    • https://easresidence.ro/app/webroot/files/userfiles/files/xajexibepar.pdfIn PDF document text
    • https://chefinhogourmet.com/wp-content/plugins/super-forms/uploads/php/files/2b0e680e3b6d67d2e7563fdd7ee12236/50477987707.pdfIn PDF document text
    • https://mindweave.co.uk/wp-content/plugins/super-forms/uploads/php/files/49f5n0690o5bs8j0eqcnor1ttj/japukevomunukitub.pdfIn PDF document text
    • https://performanceltg.com/wp-content/plugins/super-forms/uploads/php/files/7e83aaa51499215f872df968220f2ed7/26043799827.pdfIn PDF document text
    • http://www.sname.org.tw/sname/ckfinder/userfiles/files/25982317995.pdfIn PDF document text
    • http://rioairporttransfer.com/ckfinder/userfiles/files/36342514553.pdfIn PDF document text
    • http://gzbaosui.com/uploadfile/files/25188950218.pdfIn PDF document text
    • http://subventionsbetrug.de/wp-content/plugins/super-forms/uploads/php/files/6a77mr04lfejqq69u49khmqlvl/52222020935.pdfIn PDF document text
    • http://alnadaoil.com/userfiles/file/jumalalogolafevojokizepum.pdfIn PDF document text
    • https://www.zaantraining.nl/wp-content/plugins/formcraft/file-upload/server/content/files/160943e1db28bf---90776979753.pdfIn PDF document text
    • https://j-kowalewski.pl/uploads/userfiles/files/77590218850.pdfIn PDF document text
    • http://rockhouseschool.com/rockhouse/uploads/files/84179509224.pdfIn PDF document text
    • https://net-mex.hu/ckfinder/userfiles/files/xupilefo.pdfIn PDF document text
    • http://hzjywd.com/images/upload/File/mexeg.pdfIn PDF document text
    • http://wsm.hk/images/uploadfiles/file/46401610937.pdfIn PDF document text
    • http://wongkungfu.ca/clients/f/f5/f5c316b966f29b3192b3e9e3c5714b3c/File/39002249538.pdfIn PDF document text
    • http://furniture83.com/upload/files/47813347839.pdfIn PDF document text
    • http://ilovehikari.com/uploads/files/50728011825.pdfIn PDF document text
    • http://actybrain-consult.com/Upload/files/xakarakesuvik.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/zMnd8XtcwSM/uplcv?utm_term=airdrop+meaning+iphonePDF 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 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
stream_007_off00012ba2.bin decompressed-pdf-stream PDF FlateDecoded stream at offset 0x12BA2 18052 bytes
SHA-256: 3e272b34dba5d166cb5472f5a371298627f4684f10193c4a2d3730b5272e4492
font_00_sfnt_off0000e5c2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE5C2 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000fdd4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFDD4 17716 bytes
SHA-256: 347810a8c5becbdbf4835013487e11e3f141b1598643db4938b20dc8fc42d57c
font_03_sfnt_off000147cb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x147CB 10508 bytes
SHA-256: e6d303099b1bc373f8bc4eee07a88bef69e80d11f4a2de5286774f1f61af8ca1

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