Malicious PDF — malware analysis report

Static analysis result for SHA-256 c36921955a5736f9…

MALICIOUS

PDF

80.6 KB Created: 2021-09-10 00:18:42 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: 8afd8a8d6f0d38bfa5828fbb645c79d9 SHA-1: 8cf6a138c99a4db197536f79df9296cb6147e7ff SHA-256: c36921955a5736f97ec27fb158ca117d2ed3731550717e7a0ca6615c6561df84
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a PDF document flagged by multiple heuristics as malicious, including a critical ClamAV detection and an ML classifier. It contains numerous embedded URLs, with one specifically pointing to 'synerhu.ru' and a query parameter suggesting a lure related to app store issues. The PDF structure and the presence of external URIs indicate an attempt to redirect the user to a potentially malicious site, likely for phishing or to download further malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9960

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 https://synerhu.ru/uplcv?utm_term=can+not+download+apps+from+play+store PDF link annotation
    • http://camara.acessoainformacao.org/uploads/ckfinder/files/mowanerumipubijipivodimus.pdfIn PDF document text
    • http://franceplus.fr/userfiles/file/58831838168.pdfIn PDF document text
    • http://vanprodukt.cz/UserFiles/File/nufomifabumufigo.pdfIn PDF document text
    • http://ecohort.com/userfiles/files/66128542792.pdfIn PDF document text
    • https://activepymes.com/pub/file/tezer.pdfIn PDF document text
    • https://www.helpagesl.org/wp-content/plugins/formcraft/file-upload/server/content/files/16131f77e10c41---vuxumobumirasimenivi.pdfIn PDF document text
    • http://cjatkinson.com/userimages/rekarareze.pdfIn PDF document text
    • http://iccjsc.com/images/uploads/files/bufenirupokumas.pdfIn PDF document text
    • http://smartvoicecom.com/userfiles/wawuvoliwobapupamikalapar.pdfIn PDF document text
    • http://hurtmar.pl/Upload/file/22632350344.pdfIn PDF document text
    • https://muachungbaohiem.com/uploads/userfiles/file/viwuxibudipogiso.pdfIn PDF document text
    • https://hobbypet.cz/files/file/39580741437.pdfIn PDF document text
    • https://btsis.com/upload/ckfinder/files/92974692917.pdfIn PDF document text
    • http://accesoriosalmayor.com/images/userfiles/file/nafeguzimudu.pdfIn PDF document text
    • http://pwr-tech.ru/userfiles/file/fujifobojuzanonodokog.pdfIn PDF document text
    • https://landbondcorten.com/attachment/file/f7997f2dc72b6a16a8e589faba7d3f96.pdfIn PDF document text
    • http://jongauger.com/userfiles/file/92170020788.pdfIn PDF document text
    • http://markone-tools.com/upload/files/48807215301.pdfIn PDF document text
    • http://www.aamuhsv-madisonalumni.org/files/files/fikeguvabexukave.pdfIn PDF document text
    • https://parc-hotel.info/file/masobomug.pdfIn PDF document text
    • https://amartzon.store/wp-content/plugins/super-forms/uploads/php/files/06d13a7323fd55df87a6967fc9b8045c/nudilumurosanobogon.pdfIn PDF document text
    • https://chogmai.org/ckfinder/userfiles/files/71754533713.pdfIn PDF document text
    • http://acrclubinversores.com/files/galeria/files/dovopinalisu.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_off0000d6a4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD6A4 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000eebb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEEBB 10796 bytes
SHA-256: fc105bbbb6abb2f56481d4d82bca0df617e5c35995ff233eea48fadfc3db884f
font_02_sfnt_off000107c1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x107C1 17432 bytes
SHA-256: 70e5f1b01852d597abd8663876866727c437a421cb1a0f3fbabeb1a0a766e1eb