Malicious PDF — malware analysis report

Static analysis result for SHA-256 f9a19914b993f7cf…

MALICIOUS

PDF

70.6 KB Created: 2021-09-26 21:04:47 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 4b4e435410d6856818dbd4d9b97e0c3e SHA-1: 365e9c7a9f1efc3ba4fcc290384ec94e0488223d SHA-256: f9a19914b993f7cf278366ac512cce30eea30f2ba7bdc0c5056b422b4c59c337
146 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The sample was detected as malicious by ML classifiers and ClamAV, indicating a high likelihood of malicious intent. Heuristics indicate a malformed stream and the presence of numerous external URIs, suggesting it functions as a link farm. The PDF likely attempts to trick users into clicking these links, which lead to other PDF files hosted on disposable domains, potentially for SEO poisoning or further malware distribution.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9951

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
  • Malformed active-content stream length medium PDF_MALFORMED_EXPLOIT_STREAM_LENGTH
    A PDF stream that carries active/exploit-looking content has a declared /Length that does not match the recovered stream body. Malformed stream boundaries and length mismatches are common parser-evasion/supporting evidence around Reader exploit streams.
  • 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://sga.cc/uploadfile/file///2021092313490745.pdf In PDF document text
    • https://mzr-avocats.com/buddha/ckfinder/userfiles/files/varepagib.pdfIn PDF document text
    • https://myvideoclasses.com/ci/userfiles/files/jesixidawabex.pdfIn PDF document text
    • https://die-elke.de/cms/elke_page_files/file/fixarokog.pdfIn PDF document text
    • http://launensia.cz/ckfinder/userfiles/files/vedegowisolamone.pdfIn PDF document text
    • http://24x7taazasamachar.com/assets/ckfinder/core/connector/php/uploads/files/puzagirineguxufamonubev.pdfIn PDF document text
    • https://vonia.mikludava.lt/images/files/nunafadozebeduler.pdfIn PDF document text
    • https://myshalewell.com/userfiles/file/22519932818.pdfIn PDF document text
    • http://studiomuraca.eu/userfiles/files/fazikewekite.pdfIn PDF document text
    • https://phucatgarment.com.vn/ckfinder/userfiles/files/pajokezaluzivadaxe.pdfIn PDF document text
    • https://www.patisserie-flechais.fr/ckfinder/userfiles/files/73865024103.pdfIn PDF document text
    • http://ncteonline.com/userfiles/file/gewetop.pdfIn PDF document text
    • https://gites-les-bardots.com/userfiles/file/46358054802.pdfIn PDF document text
    • http://coolscape.info/images/files/74910826695.pdfIn PDF document text
    • http://elosc.com/upFile/file///ITX202109091448538636.pdfIn PDF document text
    • http://savvyais.com/userfiles/file/nokelo.pdfIn PDF document text
    • https://sindicav.com.br/ckeditor/ckfinder/userfiles/files/kitigiwepudefelo.pdfIn PDF document text
    • https://signos.larrialdiak.es/files/galeria/files/69754735989.pdfIn PDF document text
    • https://alienaquatics.com/home/gb/public_html/ckfinder/userfiles/files/41173210229.pdfIn PDF document text
    • https://shinko-tw.com/UserFiles/file/83684056275.pdfIn PDF document text
    • http://hatdesechia.com/storage/ckfinder/files/41815311827.pdfIn PDF document text
    • http://medi-sen.com/files/files/jiwiravekepekipeneture.pdfIn PDF document text
    • http://caythuocnam.org/images/files/92335565902.pdfIn PDF document text
    • http://www.egavilanes.com/ckfinder/userfiles/files/fajozasa.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/zMnd8XtcwSM/uplcv?utm_term=sandbox+games+2021PDF 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_off0000af87.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xAF87 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000c799.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC799 17364 bytes
SHA-256: 9ae81f5bbbe8b7bbeb2ee223ec16b7458d37ccd27df700335d4c266030951789
font_02_sfnt_off0000f456.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF456 10868 bytes
SHA-256: ded658f2cf24d168535fa30d3a1e66fd0286e379fb16214c9f4147771e6c68ec