Malicious PDF — malware analysis report

Static analysis result for SHA-256 51b9866e626545d1…

MALICIOUS

PDF

82.7 KB Created: 2021-09-15 02:25:37 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: 1785d510f9b62844da5ff8481fc475d3 SHA-1: e24bfa44a342caa57a1ee3df19c16547b7ad31ff SHA-256: 51b9866e626545d1d32bd014462f9b6055d129f85921e173fa8201227ecee33a
156 Risk Score

Malware Insights

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

The file was identified as malicious by ML classifiers and ClamAV, specifically flagged as a phishing trojan. Heuristics indicate it functions as a link farm, with many URLs pointing to compromised CMS uploads and disposable hosting, suggesting an attempt to distribute further malicious content or phish users. The presence of numerous unknown URLs and the PDF_SEO_DISPOSABLE_LINK_FARM heuristic strongly support this attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

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://primeodontorj.com/wp-content/plugins/super-forms/uploads/php/files/137cc99c537380ee57eb9fa5118015e6/rixudepugiwokazakivuvafiz.pdf In PDF document text
    • http://www.fullmooneye.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613a169907b53---zidupevivig.pdfIn PDF document text
    • http://www.startbatteries.gr/ckeditor/ckfinder/userfiles/files/2094818055.pdfIn PDF document text
    • https://nexapos.com/upload/files/sivelixabajon.pdfIn PDF document text
    • https://sealskinz.ru/files/file/48867090496.pdfIn PDF document text
    • https://sindicav.com.br/ckeditor/ckfinder/userfiles/files/75000033782.pdfIn PDF document text
    • https://umutfm.com/resimler/files/2090128625.pdfIn PDF document text
    • http://geology.ie/wp-content/plugins/formcraft/file-upload/server/content/files/16132f77c9b4ec---82339907768.pdfIn PDF document text
    • https://www.temsilcisitesi.com/wp-content/plugins/formcraft/file-upload/server/content/files/16134b18baf410---bulemat.pdfIn PDF document text
    • https://ita.kru.ac.th/ckfinder/userfiles/files/50972614785.pdfIn PDF document text
    • http://bamor.org/userfiles/file/xizimikiguzonima.pdfIn PDF document text
    • http://beccaro.it/userfiles/files/74569412415.pdfIn PDF document text
    • http://ctmmaximoravenna.com/ckfinder/userfiles/files/7302272861.pdfIn PDF document text
    • https://shibbirs.com/media/files/javuzufazatekopewu.pdfIn PDF document text
    • http://www.fashiongale.ro/userfiles/files/83511283301.pdfIn PDF document text
    • http://global-gypsum.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613aac575f1ab---68395024952.pdfIn PDF document text
    • http://dishandspoonproductions.com/ckfinder/userfiles/files/47807811528.pdfIn PDF document text
    • http://studiodugnani.it/userfiles/files/23360876711.pdfIn PDF document text
    • http://calisnt.com/uploads/files/20191540896.pdfIn PDF document text
    • http://luxcottage.ru/stroykamen/userfiles/file/janiworuxifox.pdfIn PDF document text
    • https://f1com.ge/wp-content/plugins/super-forms/uploads/php/files/4b2b22e5033900aa39a2c3ff4d8099e4/bemokimalodavoxafogakaba.pdfIn PDF document text
    • http://satisfytech.com/ck/upload/files/vizowega.pdfIn PDF document text
    • http://aromaonly1.com/yamituki-n/uploads/files/pakiterujeximag.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/YTWXjIUwRh0/uplcv?utm_term=how+to+download+subway+surfers+mod+apkPDF 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_off0000d461.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD461 11092 bytes
SHA-256: bef39cc264854504fb7c5d4197e02d8f5a9080d81e89876f0a0d5f8c4c6cbf9f
font_01_sfnt_off0000ee1b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEE1B 20840 bytes
SHA-256: f3ce3e59abaa8f142684bb3a44c92a9de96839f7999cfd3368e7117256373689
font_02_sfnt_off000122f7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x122F7 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1