Malicious PDF — malware analysis report

Static analysis result for SHA-256 03832aaec56cd18d…

MALICIOUS

PDF

82.1 KB Created: 2021-09-19 14:45:31 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: 3e35e76f17f755c8bab4f33b99b3bf67 SHA-1: f9614268e99ee371c065b7d82e76d5b4c7e87aaf SHA-256: 03832aaec56cd18d91c710c97d02da91c3219d1ed07e21520863614d4b51d601
156 Risk Score

Malware Insights

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

The PDF file was identified as malicious by ML classifiers and ClamAV, specifically flagged as a phishing trojan. It contains numerous links, many pointing to compromised WordPress sites or disposable hosting, suggesting a link farm designed to redirect users to malicious content. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, indicating it's not intended for direct user reading but rather as a container for these links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

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 http://www.dadosefatos.net.br/wp-content/plugins/formcraft/file-upload/server/content/files/161386ab39f700---65134765877.pdf In PDF document text
    • http://chinahanaro.com/userfiles/file///givavifu.pdfIn PDF document text
    • https://mklaassen.nl/images/file/78967961035.pdfIn PDF document text
    • http://okudshava.ru/userfiles/file/73147397713.pdfIn PDF document text
    • http://ebiocell.com/uploadfile/file///2021091713555842.pdfIn PDF document text
    • https://studiogreenwich.ru/wp-content/plugins/super-forms/uploads/php/files/133f62b347a94e21eb25733a92c2b492/fitofixovifupifose.pdfIn PDF document text
    • http://securitydirect.it/wp-content/plugins/super-forms/uploads/php/files/b9d306028be4be9ed60c5e3656ba5222/2509248435.pdfIn PDF document text
    • http://bygreenpure.com/userfiles/file/fanuzuxurataroje.pdfIn PDF document text
    • https://webmedcentralplus.com/userfiles/file/19154582546.pdfIn PDF document text
    • http://ketoanantamhcm.com/uploads/files/risexi.pdfIn PDF document text
    • http://neteyes.eu/editor_up/1600181574.pdfIn PDF document text
    • https://flylights.pl/wp-content/plugins/super-forms/uploads/php/files/gjrkv1h5njo2khkkephqba27ha/30730235060.pdfIn PDF document text
    • https://afma.pt/site/upload/file/7173285241.pdfIn PDF document text
    • https://turdv.ru/SITE/files/editor/file/23210062563.pdfIn PDF document text
    • https://yukkumpulgroup2.com/contents/files/mufototoru.pdfIn PDF document text
    • http://captaincook.hu/userfiles/file/57308321458.pdfIn PDF document text
    • https://pasarantogel.com/contents/files/juxasosedupetunukuzu.pdfIn PDF document text
    • http://birkhoffhi.com/userfiles/files/45704701011.pdfIn PDF document text
    • https://agrotehholding.ru/wp-content/plugins/super-forms/uploads/php/files/e213ffdbd60320d664b258967058ec07/41741474027.pdfIn PDF document text
    • http://noithatdangcap.vn/app/webroot/uploads/files/46607751713.pdfIn PDF document text
    • http://ayrh.internet-match.com/upload/files/89443170618.pdfIn PDF document text
    • https://paeonia.ch/userfiles/files/fizezelerepumimaxi.pdfIn PDF document text
    • http://brava-ekb.ru/userfiles/file/40261105853.pdfIn PDF document text
    • http://www.rannatennis.ee/data/upfiles/files/61935503493.pdfIn PDF document text
    • https://espritgt.com/userfiles/file/dolalezatefotebizolazob.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/S30rS-6n6vg/uplcv?utm_term=a+people%27s+history+of+the+united+states+ebookPDF 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_off0000d9b0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD9B0 17924 bytes
SHA-256: 4cd30b83929b83395577441ac91c3fbd204c2f9f07011b4c673ec473aaa197c9
font_01_sfnt_off0001084c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1084C 11056 bytes
SHA-256: ff27ce764ded9a6aefda25c13e06453649f58e49b1913bcd9076710e7e7f01fd
font_02_sfnt_off000121e2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x121E2 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1