Malicious PDF — malware analysis report

Static analysis result for SHA-256 857db1df3dde7735…

MALICIOUS

PDF

85.8 KB Created: 2021-09-20 00:16:24 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: a1c166efcf2d4d4e9a80e9b3bcdaa1ca SHA-1: ec519d4dc614bd72b9e3a8529b79cafaa10f3011 SHA-256: 857db1df3dde773512e85dcde60563d2c138a2b42e85d9c36419336aef85e3da
104 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample contains embedded JavaScript, which is often used to exploit PDF vulnerabilities or redirect users. Additionally, it features a link farm pointing to multiple compromised WordPress sites, suggesting an attempt to distribute malicious content or phish users. The ML classifier strongly indicated maliciousness, supporting these findings.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9985

Heuristics 6

  • PDF link farm points to compromised-WordPress upload storage medium PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM
    PDF contains multiple clickable links, across many distinct hosts, whose targets are random-slug files parked in the upload directories of vulnerable WordPress form plugins (FormCraft, Super Forms). This is the hallmark of the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains hosted on compromised sites. The PDF itself carries no exploit — the risk is the linked destinations.
  • 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://garglob.ru/uplcv?utm_term=melhor+jogo+de+corrida+para+android PDF link annotation
    • http://ibshop.gr/uploads/_uploads/files/12793134620.pdfIn PDF document text
    • http://aaexpansionjoint.com/wp-content/plugins/formcraft/file-upload/server/content/files/16137633c26ab5---zawozogazezusagozubamego.pdfIn PDF document text
    • http://www.inhd.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/161331fa57589c---75946141808.pdfIn PDF document text
    • https://serwisnawigacji.pl/userfiles/file/wagowowibitenabu.pdfIn PDF document text
    • https://lajovisena.com/gallery/file/beximozikiw.pdfIn PDF document text
    • https://zazilha.com.mx/wp-content/plugins/super-forms/uploads/php/files/ff4c36c18a1c29a1f3e70a5504ab3e4a/pozen.pdfIn PDF document text
    • http://ttmm.co.jp/ckfinder/userfiles/files/mijakelukisib.pdfIn PDF document text
    • http://www.jesuseslaroca.org/wp-content/plugins/formcraft/file-upload/server/content/files/1613cc29e4547f---27582183024.pdfIn PDF document text
    • http://americasbestwingsbeltsville.com/uploads/files/vifodonesazizowejag.pdfIn PDF document text
    • https://festacontinua.it/public/file/46805848714.pdfIn PDF document text
    • https://kanat.com/upload/ckfinder/files/gudalalazax.pdfIn PDF document text
    • http://seoaudytor.pl/userfiles/file/62244080609.pdfIn PDF document text
    • http://articolo17.it/siti/usr/foto/files/56916913843.pdfIn PDF document text
    • http://pension-erlkoenig.de/img/editor/file/23185383305.pdfIn PDF document text
    • https://chachachat.info/js/ckfinder/userfiles/files/kadodatadusowut.pdfIn PDF document text
    • https://thieumaunao.vn/workspace/develop/uploads/ck_upload/files/82579449962.pdfIn PDF document text
    • http://iamsoldierfit.com/wp-content/plugins/formcraft/file-upload/server/content/files/16147a70ae1d24---mexegobukedewuniwidapulav.pdfIn PDF document text
    • https://nidi.mk/ckfinder/userfiles/files/17880581551.pdfIn PDF document text
    • https://www.oasipizza.it/wp-content/plugins/formcraft/file-upload/server/content/files/1613af78fa71c4---28752212828.pdfIn PDF document text
    • http://salukool.ee/upload/userfiles/file/sulimixixurutigizi.pdfIn PDF document text
    • http://vhshf.de/File/48957330321.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_off0000e61f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE61F 20756 bytes
SHA-256: 2f939fec873b4e369d869c3055b49508b76f62206a3292ac4b3666d210196e25
font_01_sfnt_off0001195b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1195B 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00013172.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13172 10652 bytes
SHA-256: 5a0b8cc1153ed7fc2fcbe596a50c7287c6a67a3ed9cd09f32c6e69089ec16f64