Malicious PDF — malware analysis report

Static analysis result for SHA-256 f8da42b14086bcc3…

MALICIOUS

PDF

85.1 KB Created: 2021-09-21 03:10:18 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: ed0f5e162a55f6809c8e2c9bc6fa2bde SHA-1: 08e4fa16158a4ae853158a76b8a14b1ce561a268 SHA-256: f8da42b14086bcc351e522975f4e8e858847cb157de8fed941c950982ca2f457
134 Risk Score

Malware Insights

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

The PDF contains embedded JavaScript and multiple external URIs, with one pointing to 'crewmak.ru'. The ML classifier and ClamAV detection strongly indicate malicious intent. The presence of JavaScript suggests it's used to exploit vulnerabilities or redirect the user, aligning with common PDF-based malware delivery. The heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' further supports the malicious nature by indicating a link farm on disposable hosting.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9912

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
  • 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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://crewmak.ru/uplcv?utm_term=chrome+os+vdi+download PDF link annotation
    • http://www.kowel.com/ckfinder/userfiles/files/1631286549.pdfIn PDF document text
    • https://www.pactforfamilies.org/ckfinder/userfiles/files/ponup.pdfIn PDF document text
    • http://nikkenj.com/userfiles/file/19209050252.pdfIn PDF document text
    • https://www.physioaktivkramer.de/wp-content/plugins/formcraft/file-upload/server/content/files/161411ef5eff30---tegogojafeladus.pdfIn PDF document text
    • https://sibservis.com/ckfinder/userfiles/files/buperizoxosutididiw.pdfIn PDF document text
    • https://rybczewice.pl/userfiles/file/10091289698.pdfIn PDF document text
    • http://vizugy.hu/uploads/files/files/sitijekopelogeno.pdfIn PDF document text
    • http://ifaistos.reality.gr/~triantaf/images/file/75916686899.pdfIn PDF document text
    • http://tverzhilservis.ru/foktver.ru/ckfinder/userfiles/files/66261870426.pdfIn PDF document text
    • https://santehsevast.ru/userfiles/files/46104625575.pdfIn PDF document text
    • http://premiercontainerlines.com/media/ftp/file/tenivodunawi.pdfIn PDF document text
    • https://uetty.xyz/js/ckfinder/userfiles/files/mivufu.pdfIn PDF document text
    • http://www.zywawiara.pl/pliki/luzemuwavabusevupobobodo.pdfIn PDF document text
    • http://www.mostenpo.jp/userfiles/files/xaperisus.pdfIn PDF document text
    • http://openendrep.com/userfiles/files/xikenapowegodo.pdfIn PDF document text
    • https://www.ijestr.com/ckfinder/userfiles/files/53557431537.pdfIn PDF document text
    • http://khojedu.net/userfiles/file/neterisax.pdfIn PDF document text
    • https://heritagecambodiatravel.com/userfiles/file/43999433737.pdfIn PDF document text
    • https://www.bevillelecomte.com/ckfinder/userfiles/files/potubeg.pdfIn PDF document text
    • http://tecs4.com/intranet/ckfinder/userfiles/files/44348466632.pdfIn PDF document text
    • http://akcjonariusz.com/UserFiles/file/judimalaxunetakadadika.pdfIn PDF document text
    • http://gr-chem.com/upload/files/33855449498.pdfIn PDF document text
    • http://retco.ge/ckfinder/userfiles/files/11079325312.pdfIn PDF document text
    • http://www.thaiboat.net/image/upload/File/5664504913.pdfIn PDF document text
    • http://thegrcinstitute.org/app/webroot/js/ckfinder/userfiles/files/zegumoxekuzevud.pdfIn PDF document text
    • http://irodori.kir.jp/files/file/63868393023.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_off0000e45c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE45C 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000fc6e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFC6E 18976 bytes
SHA-256: 6e9bf6f2623082bc746d85f7bd3cdfe6719759b6c148d503c164a1c4b52a08c3
font_02_sfnt_off00012e67.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12E67 10600 bytes
SHA-256: 0e3b52409809e55b17d1c0a4cebfe1bfedc5c1396ed43d2c5a80250ab78431ab