Malicious PDF — malware analysis report

Static analysis result for SHA-256 861b0c3135218a8d…

MALICIOUS

PDF

73.5 KB Created: 2021-09-13 23:47:44 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: d47d1a1e91ea796e468dbd8c4e856265 SHA-1: c25cfff051bda2287f4aa872c332a1ffb777fef5 SHA-256: 861b0c3135218a8dc52f2270809611ba5f836ede186188791220dcc9e4086c6d
126 Risk Score

Malware Insights

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

The PDF file was flagged by ML classifiers and ClamAV as malicious, indicating a phishing or trojan threat. It contains numerous embedded URLs, many pointing to disposable domains, and is identified as a link farm. The presence of PDF_SEO_DISPOSABLE_LINK_FARM heuristic suggests an attempt to obscure malicious links or distribute malware through a large number of low-reputation domains. No scripts were extracted, but the overall structure and URL distribution point towards a malicious intent to redirect users to harmful content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9951

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://quangcaowebsite.vn/uploads/files/6776126845.pdf In PDF document text
    • https://nomortiga.com/contents/files/18475305358.pdfIn PDF document text
    • https://dnm.tw/uploads/files/202109011237418713.pdfIn PDF document text
    • http://lubrifianti-auto.ro/files/file/81679116916.pdfIn PDF document text
    • http://osstemcardiotec.com/files/fckeditor/file/902799818613d73447b58a.pdfIn PDF document text
    • http://joesservicecenternj.com/userfiles/files/74505968994.pdfIn PDF document text
    • http://kuresi-kaitori.com/upload/content_pic/files/13213189437.pdfIn PDF document text
    • https://tefen67.com/userfiles/files/rufed.pdfIn PDF document text
    • https://ciiinnovationsummit.com/ci/userfiles/files/nibinusokumusarej.pdfIn PDF document text
    • http://utpcomp.ru/uploads/files/68691204168.pdfIn PDF document text
    • http://techmechengineers.com/uploads/judomiwoviwosovidozenuboj.pdfIn PDF document text
    • https://seeandhearbetter.ie/img/shop/contents/gafameredigazusa.pdfIn PDF document text
    • http://steclotildehorton.ca/wp-content/plugins/formcraft/file-upload/server/content/files/16138490c62bec---37506865776.pdfIn PDF document text
    • https://dienhoanghean.com/upload/ck/files/vebajano.pdfIn PDF document text
    • https://citronixdeflection.com/nbloom/fckuploads/file/44357290262.pdfIn PDF document text
    • http://posicert.com/upload_fck/file/2021-9-2/20210902142417154597.pdfIn PDF document text
    • https://encoyun.com/calisma2/files/uploads/rabuvabelikewobe.pdfIn PDF document text
    • https://agrimal.pl/userfiles/file/burofotuvuzek.pdfIn PDF document text
    • http://biondiairsystem.it/userfiles/files/15991038838.pdfIn PDF document text
    • https://rainbowfurnitures.com/files/files/zalotosujelasenuno.pdfIn PDF document text
    • http://www.uppld.org/wp-content/plugins/formcraft/file-upload/server/content/files/16132d63c91d0d---bedawisixapaluruzuvax.pdfIn PDF document text
    • http://residencelesaline.it/userfiles/files/54716952196.pdfIn PDF document text
    • http://shiraz.sk/ckfinder/userfiles/files/4738447801.pdfIn PDF document text
    • http://asqcert.net/files/files/27674404724.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/PmAiG5ZyT-k/uplcv?utm_term=how+to+get+games+for+ppssppPDF 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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000bdd8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBDD8 16512 bytes
SHA-256: 67471f6c314a12950d4c18a7f69c0c188356236d85545488917cdf35c990b320
font_01_sfnt_off0000e866.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE866 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0001007d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1007D 10536 bytes
SHA-256: 6c85f289b3d0b41cc401147b8311b19511b1db3cdeef2c33e97cc60633a4a78c