Malicious PDF — malware analysis report

Static analysis result for SHA-256 f71b3211ded76099…

MALICIOUS

PDF

96.0 KB Created: 2021-06-20 20:34:06 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-16
MD5: 33d473b3e673febbe35293a4ad839d84 SHA-1: 73fb0a6b4d232483bd24cc5d12acdbec18096e67 SHA-256: f71b3211ded760993bd8fbf7710fe6f8b0eb5bb7c334fc260056902b86011320
156 Risk Score

Malware Insights

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

The PDF file was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. It contains numerous embedded URLs that point to various domains, many of which appear to be compromised WordPress sites or disposable hosting. The document body is heavily obfuscated and contains metadata related to wkhtmltopdf, suggesting it was generated programmatically rather than being a user-authored document.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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.
  • 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://chcial.ru/uplcv?utm_term=ielts+speaking+off+topic PDF link annotation
    • http://curry-box-deluxe.de/userfiles/file/wavadulukewaxafaxudok.pdfIn PDF document text
    • http://eko-inwest.eu/upload/file/75055245368.pdfIn PDF document text
    • https://travels-ukraine.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606f6df842ce6---rasuvakariker.pdfIn PDF document text
    • https://finestblogger.de/wp-content/plugins/super-forms/uploads/php/files/hmikvhths5usrt67q5o01i3aug/ripubijito.pdfIn PDF document text
    • https://asiquim.com/ckfinder/userfiles/files/12987010453.pdfIn PDF document text
    • http://cohensevents.com/clients/74638/File/34206026176.pdfIn PDF document text
    • https://backcountryplayground.com/wp-content/plugins/super-forms/uploads/php/files/f81444e5047b8174f0cbfe7423f5430e/rawapaxu.pdfIn PDF document text
    • http://lirealestatelitigator.com/wp-content/plugins/super-forms/uploads/php/files/9b0b9f56361e64d2b9acc813831d3231/davupukominujipozob.pdfIn PDF document text
    • https://ukdirectremovals.com/wp-content/plugins/super-forms/uploads/php/files/8577a2428c09513494e5cfd963eba959/darekolivasarudixorazu.pdfIn PDF document text
    • http://axwelindia.com/uploads/jopifu.pdfIn PDF document text
    • http://kennyre.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c0d3ba3d5cb---67395478186.pdfIn PDF document text
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609e38346214e---9710453661.pdfIn PDF document text
    • https://discoverapartmentsforrent.com/wp-content/plugins/super-forms/uploads/php/files/36642f3a0e69fb9066767064c19eeb4e/54415922067.pdfIn PDF document text
    • https://robinio.de/wp-content/plugins/super-forms/uploads/php/files/3ldmg5icvl2ad0986n0qonojel/55715483380.pdfIn PDF document text
    • http://dokumsuzgec.com/userfiles/files/vexatalilunox.pdfIn PDF document text
    • https://ventana-sur.com/wp-content/plugins/formcraft/file-upload/server/content/files/160aae8757ef9e.pdfIn PDF document text
    • https://bruceautoservice.com/files/file/veduzasoxiwavopitopanu.pdfIn PDF document text
    • https://all-stage-meditation.tw/uploads/files/60bbc16ace242.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • 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://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off000138dd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x138DD 5088 bytes
SHA-256: 9a0a320e33103e83c992194684d989a3aa98439ca7ae70de53ef38e97e8ce66b
font_01_sfnt_off00014a4d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x14A4D 11368 bytes
SHA-256: ef0b96c98d8b117ffdfd1c1bf8af49a407c72ca156db260e812140791aaddc57