Malicious PDF — malware analysis report

Static analysis result for SHA-256 87d8c00c57754828…

MALICIOUS

PDF

75.7 KB Created: 2021-06-15 17:04:40 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-23
MD5: 3a3028fd1b03acba397d98fe13e25c3b SHA-1: 95cb395f3f08be13ebaa0f7c39d4df261b7f0676 SHA-256: 87d8c00c5775482820e6fb0a5f9bbc49056c5d0b4ff63a51cb942b0ca663e127
156 Risk Score

Malware Insights

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

The PDF file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It contains numerous external links, many pointing to compromised CMS upload directories, suggesting it's part of a link farm designed to redirect users to malicious sites. The document body, though heavily obfuscated, contains text related to 'Ielts task 2 questions and answers', which is likely a lure to attract victims.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 6

  • 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 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://coretry.ru/uplcv?utm_term=ielts+task+2+questions+and+answers PDF link annotation
    • https://dfa-finanz.de/wp-content/plugins/formcraft/file-upload/server/content/files/1607527f34837d---tudakoxuwigadotugu.pdfIn PDF document text
    • https://alkalacarservice.com/public_html/userfiles/file/vutifilujo.pdfIn PDF document text
    • http://worksafeorg.com/wp-content/plugins/super-forms/uploads/php/files/46tnllc53ricj4n779bbgpesn3/wumadozotonikogiza.pdfIn PDF document text
    • http://www.myhhsi.com/wp-content/plugins/super-forms/uploads/php/files/d54378d54cd7a6de4cdcd61f3ad91951/kenurusavusugedimen.pdfIn PDF document text
    • http://www.itbaloch.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607041c52d45a---favamumikegoxidokifo.pdfIn PDF document text
    • http://luvnchrlysenglishtoys.com/clients/861429/File/62298895433.pdfIn PDF document text
    • https://40parables.com/wp-content/plugins/super-forms/uploads/php/files/f54b302111f3629cbcbfac723fe45355/47618931580.pdfIn PDF document text
    • http://www.idenet.net/wp-content/plugins/formcraft/file-upload/server/content/files/16080590dd0c45---bizomefirewataxurebowim.pdfIn PDF document text
    • https://www.landalastadservice.com/wp-content/plugins/formcraft/file-upload/server/content/files/16092b2648b8c0---rizomisobexipu.pdfIn PDF document text
    • https://atlasautoglass.com/wp-content/plugins/formcraft/file-upload/server/content/files/160712b37ae118---20122774011.pdfIn PDF document text
    • https://sheenabusesandcoaches.com/userfiles/file/wonorog.pdfIn PDF document text
    • https://www.adler-leitishofen.de/wp-content/plugins/formcraft/file-upload/server/content/files/1606d5fea67ec5---ketipu.pdfIn PDF document text
    • http://www.firengo.com/userfiles/files/94817388072.pdfIn PDF document text
    • http://phdpecs.hu/userfiles/files/90136934684.pdfIn PDF document text
    • https://www.synergyheart2heart.team/wp-content/plugins/super-forms/uploads/php/files/fn240tcco533di8io100tt3824/botavi.pdfIn PDF document text
    • https://humanistbeauty.com/wp-content/plugins/super-forms/uploads/php/files/1ku2vp1h317duf74o64r3lg3mc/63748393200.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://www.daltonmaag.com/In 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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000df6c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDF6C 5052 bytes
SHA-256: adfd0d6b839039ef3edbf84cb78b2d893d500520ae47eb4143b8f408be7abbdc
font_01_sfnt_off0000f0b2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF0B2 10388 bytes
SHA-256: 08e5dfbdf68cc153f601be60b1ecf6cb8d8d6a0e1482ace688e89f2a8ec34c21
font_02_sfnt_off000113f1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x113F1 4324 bytes
SHA-256: 4fcfa7c68d76e23b667942a3ac892d2d5d88346478daafc61479ad4df4af3dd3