Malicious PDF — malware analysis report

Static analysis result for SHA-256 cf0878775ec70962…

MALICIOUS

PDF

70.5 KB Created: 2021-09-17 18:11:38 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: 4e6ae6f2ba739c4d48d3d05821b19473 SHA-1: 7326c09b388b6330b3b002144f8feae89def86d2 SHA-256: cf0878775ec7096232a08a3f424c4d2dd15a4be39f3370e30401ec07e9e0895a
126 Risk Score

Malware Insights

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

The file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. The PDF contains numerous embedded URLs pointing to a link farm, suggesting a phishing or SEO manipulation tactic. The heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' specifically flags this behavior, and the presence of many unknown URLs supports this. While no scripts were extracted, the overall structure and heuristic firings point to a malicious document.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9947

Heuristics 5

  • 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.
  • 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 http://dobrejaja.com/Upload/file/tazen.pdf In PDF document text
    • http://xn--rssx31a7tec6p.com/upload/userfiles/files/20210910014734.pdfIn PDF document text
    • http://mikol-styl.cz/userfiles/file/42362043924.pdfIn PDF document text
    • http://kalkulacka-hypo.cz/userfiles/files/5001102940.pdfIn PDF document text
    • http://ghibms.com/userfiles/files/73614997266.pdfIn PDF document text
    • http://abwgulfport.com/uploads/files/41165622864.pdfIn PDF document text
    • http://abbeytraining.net/userfiles/file/jasabexegoxuvasega.pdfIn PDF document text
    • http://les-dvorik.ru/userfiles/file/resusumabule.pdfIn PDF document text
    • https://alnahamgroup.com/userfiles/file/faroxe.pdfIn PDF document text
    • https://brazilairporttransfers.com/ckfinder/userfiles/files/66518556873.pdfIn PDF document text
    • https://tonthephunglan.vn/upload/files/bajelizidofotipuno.pdfIn PDF document text
    • https://santa.sg/images/users/00000000/files/88272128516.pdfIn PDF document text
    • http://eortak.com/img/fck_temp/file/sulubopoliperesolapi.pdfIn PDF document text
    • http://becro-plast.hr/wp-content/plugins/formcraft/file-upload/server/content/files/16140ab5b69f28---fokozuragifosaraxow.pdfIn PDF document text
    • https://groupunsur3.com/contents/files/togipenul.pdfIn PDF document text
    • http://geneolock.com/locktactyuma/userfiles/file/vipivizumo.pdfIn PDF document text
    • http://placc.info/up_image/48492073412.pdfIn PDF document text
    • http://paulbwatkinslaw.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/98253224230.pdfIn PDF document text
    • https://karpataljaturizmus.hu/upload/56130242604.pdfIn PDF document text
    • https://leise.ru/admin/ckfinder/userfiles/files/91191706630.pdfIn PDF document text
    • http://land89.com/ckupload/files/taxareta.pdfIn PDF document text
    • http://eatatrudy.com/uploads/files/78495308599.pdfIn PDF document text
    • http://kfoodntea.com/dataroom/file/korep.pdfIn PDF document text
    • http://hwangtosidae.com/userData/ebizro_board/file/35384879103.pdfIn PDF document text
    • http://uekekb.ru/!upload/files/tujuwesixopiwikijaxola.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/A3Ryygt5BCM/uplcv?utm_term=hexadecimal+representation+calculatorPDF 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_off0000b4a1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB4A1 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000ccb8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCCB8 10868 bytes
SHA-256: a379c67e13550299fc5385d647cc7a48049b743187557553b05c795ad5ceee1a
font_02_sfnt_off0000e5b4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE5B4 15232 bytes
SHA-256: 20bb94b2430cf4e94aa03ef01314bf825a8aac03a2d3b6f93336350dc83d8f6f