Malicious PDF — malware analysis report

Static analysis result for SHA-256 81bf67449f38d2e7…

MALICIOUS

PDF

68.6 KB Created: 2021-09-11 04:28:31 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 0303239f0b17f58856994628aa05d7b1 SHA-1: b31dfa2c09bb4a9fdd281422de65b6f769acf338 SHA-256: 81bf67449f38d2e73fbe1b0ca091f25d107f69eec341538d2d7118120ec69262
166 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1553.004 Security Software Blocking

This PDF file was detected as malicious by ClamAV and an ML classifier. It contains numerous embedded URLs, many of which point to PDF files, suggesting a link farm or redirection mechanism. Crucially, the file contains an instruction to disable security software, a strong indicator of malicious intent. While no scripts were explicitly extracted, the presence of embedded URLs and the security bypass heuristic suggest the document is designed to lure the user into a compromised state, likely to download further payloads.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9973

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
  • Security software disable instruction high SE_SECURITY_BYPASS
    Document instructs the user to disable antivirus or security software — unusual for ordinary documents and high-risk in an unsolicited file
  • 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://coffotea.com/uploads/files/202109031030546366.pdf In PDF document text
    • http://associatedreclaimed.com/userfiles/files/kivawetirupepatuwi.pdfIn PDF document text
    • http://rayer.cn/d/files/zoletujefubekuwaribelofix.pdfIn PDF document text
    • http://canxetaianhduc.com/images/file/99414778985.pdfIn PDF document text
    • http://www.chp.pl/ckfinder/userfiles/files/35329638349.pdfIn PDF document text
    • http://xuanfe.com/uploads/FCKeditor/file/lunamulizifowaxiramaf.pdfIn PDF document text
    • http://monticellotownship.org/userfiles/file/zifavaxiv.pdfIn PDF document text
    • https://designmaster.in/scgtest/eec-new/codelibrary/ckeditor/ckfinder/userfiles/files/34968401155.pdfIn PDF document text
    • https://idfusionllc.com/wp-content/plugins/super-forms/uploads/php/files/f40f7fe89593fe73f672284f9e6d679c/2531868536.pdfIn PDF document text
    • http://rockhouseschool.com/rockhouse/uploads/files/55425947563.pdfIn PDF document text
    • http://khocabien.com/uploads/files/nukazokifakatoxamukotome.pdfIn PDF document text
    • http://noxsun.com/jingkelun/userfiles/files/20210911003453.pdfIn PDF document text
    • http://giteduguedesboires.com/userfiles/file/xuzarozoda.pdfIn PDF document text
    • https://sharzh-ufa.ru/wp-content/plugins/super-forms/uploads/php/files/db72f91761b13334ab1bfc3de07dbbf4/42261552926.pdfIn PDF document text
    • http://ngnjl.com/userfiles/files/72167870517.pdfIn PDF document text
    • https://aiwcecckolkata.org/FCKeditor/file/8129796167.pdfIn PDF document text
    • https://hglobaltourb2c.com/FileData/ckfinder/files/20210910_81B6EDB8C1CC6EBE.pdfIn PDF document text
    • https://mobilpetrol.olajpark.hu/files/files/luvafafefeloveforug.pdfIn PDF document text
    • https://virker-ikke.dk/files/4123028231.pdfIn PDF document text
    • http://php-lounge.de/userfiles/file/lirajubojaxogili.pdfIn PDF document text
    • https://adci.vn/data/upload/file/mezoxak.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/ngfLrbzwjls/uplcv?utm_term=android+firewall+disablePDF 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_off0000ad5d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xAD5D 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000c56f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC56F 15736 bytes
SHA-256: 4c0038eea05ea04702d9e97afa41f8029bfd11b0a6879e8b84a6ae2cd73e47a6
font_02_sfnt_off0000ed79.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xED79 10456 bytes
SHA-256: a845a644a64f16380539adf0145f1b5d668d645aeb628a823137f3ad23af6c84