Malicious PDF — malware analysis report

Static analysis result for SHA-256 3841fd44e138f377…

MALICIOUS

PDF

75.6 KB Created: 2021-09-21 04:50:00 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 3d18f7abd6d53880a4c3ad7497b27676 SHA-1: 14b1bbcf05383f3980f4b2c77d7e26ef6dd437ab SHA-256: 3841fd44e138f377f13d08017782c973ed40c9fcb26ff11b542153779133b4f9
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file is identified as malicious by ClamAV and an ML classifier, with heuristics indicating it functions as a link farm on disposable hosting. The embedded URLs and the PDF structure suggest an attempt to direct users to potentially harmful websites, likely for phishing or malware delivery. No scripts were extracted, but the overall pattern points to a malicious PDF designed for initial access.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9973

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://queure.ru/uplcv?utm_term=lewis+black+thanks+for+risking+your+life+streaming PDF link annotation
    • http://uklearningnetwork.com/userfiles/file/89227755695.pdfIn PDF document text
    • https://www.hs-hofgastein.salzburg.at/ckfinder/userfiles/files/61712639757.pdfIn PDF document text
    • http://hit-air.pro/ckfinder/userfiles/files/kepejovotenaregape.pdfIn PDF document text
    • http://ugyvednok.hu/userfiles/file/90649063531.pdfIn PDF document text
    • http://marienoellebermond.com/img/uploaded/file/93513034282.pdfIn PDF document text
    • https://copab.tn/216mag.svn/uploads/files/45889381628.pdfIn PDF document text
    • https://olterus.info/contents/files/juruvivuguvoxopirivowumod.pdfIn PDF document text
    • http://atomiccm.com/userfiles/files/24052764315.pdfIn PDF document text
    • https://khonggiansangtao.com/platformecom/img/upload/file/nodekajifap.pdfIn PDF document text
    • https://weborder.cloud/userfiles/file///zegedupoliluzunofotiwim.pdfIn PDF document text
    • http://himalayakebab.com/shipinc/userfiles/files/18688734600.pdfIn PDF document text
    • http://centromedicoveterinarioadda.com/userfiles/files/fepujaxikevowutapubena.pdfIn PDF document text
    • https://sapporopools.com/contents/files/81285217194.pdfIn PDF document text
    • http://hotechike.com/files/files/pusuliwesefutobusuremuj.pdfIn PDF document text
    • https://dmddsgn.com/wp-content/plugins/super-forms/uploads/php/files/eff9e66d12a35acac5606dc180bae334/22088408777.pdfIn PDF document text
    • http://jinruily.com/UploadFile/file/20210920173544740.pdfIn PDF document text
    • https://charming-dc.com/uploads/files/202108311725568401.pdfIn PDF document text
    • https://nepalipublisher.com/ckfinder/userfiles/files/56930225453.pdfIn PDF document text
    • http://oralrem.kz/ckfinder/userfiles/files/99221523229.pdfIn PDF document text
    • https://quangcaowebsitecomvn.xemlaco.com/uploads/files/83241919279.pdfIn PDF document text
    • http://entryexpress.online/chapter_images/files/faxomegunimeme.pdfIn PDF document text
    • https://conexusinternational.com/ckfinder/userfiles/file/93880289293.pdfIn PDF document text
    • https://dmitrovka-zn.ru/admin/ckfinder/userfiles/files/75350883008.pdfIn PDF document text
    • http://acm-medicali.it/userfiles/files/pisafamegogubuvelixok.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_off0000bffc.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBFFC 11272 bytes
SHA-256: 4202c8d102dcb9749138ab136a53d7ef6a6e690e7e84fb94e9cecbfda9ce6e8c
font_01_sfnt_off0000da5f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDA5F 17672 bytes
SHA-256: 4deef809c9e992af453b3748938dff2d0f9640e288fcb69c8b6257c4cc78f93a
font_02_sfnt_off0001081e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1081E 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1