Malicious PDF — malware analysis report

Static analysis result for SHA-256 a41833b8bf2525e4…

MALICIOUS

PDF

92.8 KB Created: 2021-10-11 11:10:33 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: 37409f3ec6e8816d371cbf8341d0dc51 SHA-1: aa1e2e835eaa8eea730581f3cea1e450bc370a2c SHA-256: a41833b8bf2525e49a85de49ea8e15d5e35fcb41566236f8afa3bd24c085a21c
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample was flagged by multiple heuristics, including a critical ClamAV detection and an ML classifier, indicating malicious intent. The PDF contains numerous embedded URLs, many of which are part of a link farm on disposable hosting, suggesting a phishing or malware distribution scheme. The presence of external URIs and the 'link farm' heuristic strongly support an attack pattern focused on redirecting users to potentially harmful sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9935

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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=legally+blonde+123movies+free PDF link annotation
    • http://kielcenoca.pl/files/file/64053472551.pdfIn PDF document text
    • https://2winit.com/Files/files/gemudefiza.pdfIn PDF document text
    • http://jinyezi.cn/upload/jofowofet.pdfIn PDF document text
    • http://precisao.org/files/files/pekafok.pdfIn PDF document text
    • https://www.pirkitpadangas.lt/ckfinder/userfiles/files/toteliwajegerixati.pdfIn PDF document text
    • https://poldercuptrofee.nl/site/admin/ckfinder/userfilesfiles/bipidibobivetajexulog.pdfIn PDF document text
    • http://sdes.in/uploads/47426179706.pdfIn PDF document text
    • http://manu-transport.com/documents/file/14925845549.pdfIn PDF document text
    • http://debten.net/UserFiles/File/pabobe.pdfIn PDF document text
    • https://khonggiansangtao.com/platformecom/img/upload/file/selofapuvuzagep.pdfIn PDF document text
    • https://takarasushimn.com/userfiles/files/22789011063.pdfIn PDF document text
    • http://limobebe.com/userfiles/files/97027316025.pdfIn PDF document text
    • https://bselink.com/userfiles/file/vajim.pdfIn PDF document text
    • http://spielundlicht.de/content_provider/documents/files/25893302486.pdfIn PDF document text
    • http://box8websites.com/ckfinder/userfiles/files/65390289960.pdfIn PDF document text
    • https://postelezmasivu-olomouc.cz/ckfinder/userfiles/files/derepugovol.pdfIn PDF document text
    • http://www.slenderclub.cz/ckfinder/userfiles/files/59770181387.pdfIn PDF document text
    • https://www.larche-de-jules.fr/ckfinder/userfiles/files/34701087748.pdfIn PDF document text
    • https://ita.kru.ac.th/ckfinder/userfiles/files/sasunizawovow.pdfIn PDF document text
    • http://smithmurdock.com/wp-content/plugins/formcraft/file-upload/server/content/files/161328a765526d---gazowuzuwivep.pdfIn PDF document text
    • https://yukkumpulgroup1.com/contents/files/41256509462.pdfIn PDF document text
    • http://vibrosystem.ro/wp-content/plugins/formcraft/file-upload/server/content/files/16132091da0b31---favipaxujevud.pdfIn PDF document text
    • http://whuntex.ru/userfiles/file/zolubeg.pdfIn PDF document text
    • https://medtek.vn/storage/file/kabusujolezu.pdfIn 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://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_off00010148.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10148 19528 bytes
SHA-256: cc67ec45be268273abbb6a309912ba4cc3ee03bd444e94ba30aff7224a3cd160
font_01_sfnt_off0001338c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1338C 11220 bytes
SHA-256: 8a44efab8ce70c5332770bff04ca27ab74489e97a038acbb486cedd791f18494
font_02_sfnt_off00014db2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x14DB2 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1