Malicious PDF — malware analysis report

Static analysis result for SHA-256 fc689ac9428ef41a…

MALICIOUS

PDF

74.0 KB Created: 2021-09-17 21:37:06 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: d6cf4cbf2c2e79e02c0cb8ecc011e428 SHA-1: 823c22fc6a53211930bbc440cdd965a09fcfce72 SHA-256: fc689ac9428ef41a8af4ec67d74e43e29f9734293de2cf94811092ba756cce9a
104 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF contains embedded JavaScript and a large number of external URIs, many of which point to PDF files hosted on compromised WordPress sites. This suggests the document is part of a link farm designed to distribute further malicious content or lead users to phishing sites. The ML classifier also strongly indicated maliciousness.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9947

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://archism.ru/uplcv?utm_term=wheel+of+fortune+answers+movie+title PDF link annotation
    • http://canadianrockies.ca/files/file/80999762973.pdfIn PDF document text
    • https://wigs4less.net/nbloom/fckuploads/file/23603008312.pdfIn PDF document text
    • http://piri-piri.pl/ckfinder/userfiles/files/67699787074.pdfIn PDF document text
    • http://ulv-fogger.ru/d/files/77354251043.pdfIn PDF document text
    • https://oncallanatomist.com/ckfinder/userfiles/files/kasemenimaj.pdfIn PDF document text
    • http://trevorhannant.com/42201938972.pdfIn PDF document text
    • http://intertribo.sk/files/96076228909.pdfIn PDF document text
    • http://newo.ru/files/files/revunez.pdfIn PDF document text
    • http://energyexcess.com/userfiles/file/tasufarexevonazapavi.pdfIn PDF document text
    • https://aldea.work/wp-content/plugins/super-forms/uploads/php/files/c37e6e44d0ff54da959c92d094e5abd7/xugenibivoru.pdfIn PDF document text
    • http://lirealestatelitigator.com/wp-content/plugins/super-forms/uploads/php/files/7bead44f6fa6e6e94f3f1748b1516779/1669561861.pdfIn PDF document text
    • http://www.huescalamagiaenfotos.com/userfiles/files/wufinanagimavusirelerowo.pdfIn PDF document text
    • http://makaifruits.com/wp-content/plugins/formcraft/file-upload/server/content/files/161309e77f3e60---36670599075.pdfIn PDF document text
    • http://klingende-zeder.de/wp-content/plugins/formcraft/file-upload/server/content/files/16144a434c1525---putaromixadumazomebureb.pdfIn PDF document text
    • http://2015.letnifestiwal.pl/ckfinder/userfiles/files/69504092596.pdfIn PDF document text
    • http://usaoxin.com/userfiles/2021-9/file/53832515693.pdfIn PDF document text
    • https://santa.my/images/users/00000000/files/69722995814.pdfIn PDF document text
    • https://lescourailleurs.com/upload/editor/file/41128041282.pdfIn PDF document text
    • https://pabausa.org/wp-content/plugins/formcraft/file-upload/server/content/files/161307a6163fa1---43120740837.pdfIn PDF document text
    • http://aias.pnu.ac.th/ckfinder/userfiles/files/xinirojevesifazusubusav.pdfIn PDF document text
    • http://theemasternetworker.com/ckfinder/userfiles/files/62438349460.pdfIn PDF document text
    • https://www.cdscabling.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/16143c696e3d41---93213914780.pdfIn PDF document text
    • https://www.santaterezinha.com.br/js/ckfinder/userfiles/files/laweriganasebufulofiwudo.pdfIn PDF document text
    • https://aihr-iadh.org/uploads/FCK_files/file/88077943908.pdfIn PDF document text
    • https://jewfri.kr/files/image/files/87803144398.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_off0000bdca.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBDCA 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000d5dc.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD5DC 16968 bytes
SHA-256: 67530f24d1632b311d422b6dfc11810860a5c6b1ab1769931b07326a9f0596ec
font_02_sfnt_off000101cd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x101CD 10724 bytes
SHA-256: c08e56e86d4cb345c4eaf3c214ebf43d236e73a3b280ab3c453fe93842d70c69