Malicious PDF — malware analysis report

Static analysis result for SHA-256 a3a1206c651b6356…

MALICIOUS

PDF

91.1 KB Created: 2021-10-05 11:42:22 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-31
MD5: ba4cdd732c35a3167d8e779022083b59 SHA-1: e5f23df2dddd33608624f6f57c7dc0f5f124b8d6 SHA-256: a3a1206c651b635662c8224c3fc1127119437c2a19681e556a92589b0bb87e9c
126 Risk Score

Malware Insights

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

The file was detected as malicious by ML classifiers and ClamAV, indicating a high likelihood of malicious intent. It contains numerous embedded URLs pointing to external PDF files, suggesting it functions as a link farm or part of a distribution network. The PDF_SEO_DISPOSABLE_LINK_FARM heuristic specifically flags this behavior, indicating a tactic to manipulate search engine results or distribute further malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9932

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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 http://belv.ru/userfiles/file/81969418100.pdf In PDF document text
    • http://guides2alpes.fr/uploads/file/nategofefepovedo.pdfIn PDF document text
    • https://epiphanych.com/images/file/51772991617.pdfIn PDF document text
    • https://ctners.com/ckfinder/userfiles/files/42544545221.pdfIn PDF document text
    • https://promtour-rural.ro/userfiles/file/navexunabanefekum.pdfIn PDF document text
    • https://doublehaircenter.com/upload/ckfinder/files/38743703331.pdfIn PDF document text
    • http://intertexmedical.com/userfiles/files/82699115553.pdfIn PDF document text
    • http://cpviettin.com/upload/files/54494670059.pdfIn PDF document text
    • http://carneslaw.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/pejekozizolizeferisa.pdfIn PDF document text
    • http://hzjksj.com/images/upload/File/33176797654.pdfIn PDF document text
    • http://mitsubishilongbien.vn/images/ckeditor/files/veladotajugiper.pdfIn PDF document text
    • https://rafaellopezehijo.com/upload/files/devetezetaje.pdfIn PDF document text
    • http://markasib.ru/ckfinder/userfiles/files/19427716085.pdfIn PDF document text
    • http://www.siscard.com/wp-content/plugins/formcraft/file-upload/server/content/files/1615b46903dab8---rebimunimezasivatoj.pdfIn PDF document text
    • http://tele-fonika.pl/upload/file/purelisewotepawu.pdfIn PDF document text
    • http://t-cso.com/upload/file_folder/file/lojusirasewugigux.pdfIn PDF document text
    • https://xn--fct5g39pjpo.tw/upload/leakstop/files/ralolo.pdfIn PDF document text
    • https://xn--78-6kce7dfhb9dwb.xn--p1ai/wp-content/plugins/super-forms/uploads/php/files/355d47263edb7781c555a9d19a81112a/xufogovoruxubugavepowe.pdfIn PDF document text
    • https://renetravel.ro/images/files/nowemexizefufibumajifek.pdfIn PDF document text
    • http://ainut.fi/userfiles/file/xatax.pdfIn PDF document text
    • http://mitcostruttori.it/userfiles/files/saweribumima.pdfIn PDF document text
    • http://ke-sen.com/userfiles/file/1631366626.pdfIn PDF document text
    • http://findingthegrey.com/userfiles/file/bafinuximaxuzefawawude.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/1xuhb7AK25c/uplcv?utm_term=deer+tick+these+old+shoesPDF 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 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000e006.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE006 17644 bytes
SHA-256: 71715472033673366de1c2009da65077c0387aeadbc3aadf5d9a0302e709d2aa
font_01_sfnt_off0000fa74.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFA74 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0001128b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1128B 10296 bytes
SHA-256: 8fe3cd18eb6c4b08355ec498f55332b59b495f9f6a822a8e63e1916bf5123029
font_03_sfnt_off000129dd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x129DD 20512 bytes
SHA-256: 9cc4185eaf26e5db3bed01247b8f95c4f4a99bb53091942af13791fd4a33c71a