Malicious PDF — malware analysis report

Static analysis result for SHA-256 fe18882e9a01e0dd…

MALICIOUS

PDF

79.4 KB Created: 2021-06-09 08:45:18 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-12
MD5: 6a0021cbb07145e3ee991805faed2f9e SHA-1: 8a0fcb7641d02ee852351e2e8ae9bef1608ff7bc SHA-256: fe18882e9a01e0dddb8811be95d8e3745fe32f4f822fd932e9b2b7b694cf8029
196 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript

This PDF file contains numerous links to external websites, many of which are hosted on compromised WordPress installations. The document body, though heavily obfuscated, suggests a lure related to 'simple present tense worksheet pdf with answers'. The presence of PDF_RANDOM_URL_LINK and PDF_SEO_DISPOSABLE_LINK_FARM heuristics indicates a pattern of distributing malicious content through link farms. The ML classifier and ClamAV detection strongly suggest malicious intent, likely to download a second-stage payload.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 7

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • PDF link to algorithmically-generated URL high PDF_RANDOM_URL_LINK
    PDF contains a clickable HTTP(S) link whose host looks algorithmically generated (pronounceable-random labels) and whose path/query carries a long high-entropy token. This is the randomized-redirector pattern of malspam phishing lures — the visible document is only a prompt — not a PDF parser vulnerability.
  • 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://oniceh.ru/uplcv?utm_term=simple+present+tense+worksheet+pdf+with+answers PDF link annotation
    • http://c2mag.com/wp-content/plugins/formcraft/file-upload/server/content/files/160bad089e8ef7---depiratuvikimowiw.pdfIn PDF document text
    • http://queuemanagementsystems.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608446121562c---renafiriwasezun.pdfIn PDF document text
    • https://www.adelaarenergy.com/wp-content/plugins/super-forms/uploads/php/files/ktjl9mht069826gbdm14khiekg/41161918153.pdfIn PDF document text
    • https://playgametoday.ru/wp-content/plugins/super-forms/uploads/php/files/1a49c18355a5fe8f6cef6be92aad8bc1/67645349429.pdfIn PDF document text
    • http://thementalhealthadvocates.org/files/userfiles/file/totupeg.pdfIn PDF document text
    • https://dmvassociates.com/wp-content/plugins/super-forms/uploads/php/files/5b6727dc9dd782a2373ce765d8b2b566/85648541686.pdfIn PDF document text
    • https://laser-arena.ch/wp-content/plugins/formcraft/file-upload/server/content/files/16074900c57acb---bakibaxibaju.pdfIn PDF document text
    • http://fredericjean.net/oplusco/file/limapufulabup.pdfIn PDF document text
    • https://bjsteelvietnam.com/upload/fck/file/danuxoluxugifenumojeg.pdfIn PDF document text
    • http://www.thelawchamber.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608fcc9b0ab4f---zasawuwirafeti.pdfIn PDF document text
    • http://mirembeestate.co.ug/wp-content/plugins/formcraft/file-upload/server/content/files/160751aae9d376---19840768228.pdfIn PDF document text
    • http://scandirent-new.ru/uploads/assets/file/85884451984.pdfIn PDF document text
    • https://clubforeducation.com/FCKeditor/userfiles/file/vujopuzoxoli.pdfIn PDF document text
    • http://www.sunarnuricomuisvealisverismerkezi.com/wp-content/plugins/super-forms/uploads/php/files/7d74uhc7quoilij8ecfnb9q8j6/25421072271.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
    • 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_off0000e39f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE39F 5540 bytes
SHA-256: c6eb2377efb87fb4158a3c9bd7e48c8d3b03f2581c50c116d60544232c8333e1
font_01_sfnt_off0000f658.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF658 10672 bytes
SHA-256: 54a6fa7ef77bf92e594731ed2acd820a7dc691b225d00c5b1f91abcb1fe53f54
font_02_sfnt_off00011b24.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11B24 16204 bytes
SHA-256: e93acd332f5893643511f4cefd38969ad5c744ad1b08842a788b6be7d277dd15

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