Malicious PDF — malware analysis report

Static analysis result for SHA-256 53f25b7ec56bca8b…

MALICIOUS

PDF

89.0 KB Created: 2021-07-30 12:44:55 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: ff2ecab96b4c1c66e88bae52f0d6b63c SHA-1: 3c0528fe7de94c3769465815e586316a68537dcd SHA-256: 53f25b7ec56bca8ba2e3ea9a6d852b662257db1fa58a1188300ac2e92cbdac5c
156 Risk Score

Malware Insights

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

The PDF was flagged by ClamAV as a phishing trojan and a machine learning model indicated a high probability of maliciousness. Heuristics identified it as a link farm, with many URLs pointing to compromised CMS uploads and disposable hosting. The document body is heavily obfuscated and unreadable, suggesting an attempt to hide its true purpose, which is likely to redirect users to malicious sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9986

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
  • 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.
  • 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://kovacsoltvaskerites.hu/images/file/67776481354.pdf In PDF document text
    • https://vivekanandbawwa.com/userfiles/file/32146757454.pdfIn PDF document text
    • https://www.themeshcowork.com/wp-content/plugins/super-forms/uploads/php/files/c70c3046ec1b3bc5379b2ecc07cc049d/92524230141.pdfIn PDF document text
    • https://elicopter-de-inchiriat.ro/wp-content/plugins/formcraft/file-upload/server/content/files/160bc1bf2270a6---82300260430.pdfIn PDF document text
    • https://www.straightmyteeth.com/wp-content/plugins/super-forms/uploads/php/files/8b746fd47464e9b9e835fbb4c5257d5a/51937885615.pdfIn PDF document text
    • https://alphacleanwashing.com/wp-content/plugins/super-forms/uploads/php/files/465f31948af781d6fb04af03fa0a50bf/45734652658.pdfIn PDF document text
    • https://www.swx.global/wp-content/plugins/super-forms/uploads/php/files/e9f220b0292b2cca70210597eb8ef83e/3813771985.pdfIn PDF document text
    • https://bruceautoservice.com/files/file/bebaxapikidojifixeb.pdfIn PDF document text
    • https://www.americanapi.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609240a524723---51262697443.pdfIn PDF document text
    • http://www.wallisandemmanuel.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c8949f5611d---lovumezute.pdfIn PDF document text
    • http://www.mkkdigital.pt/wp-content/plugins/formcraft/file-upload/server/content/files/1607e0a6e971d6---36801985809.pdfIn PDF document text
    • https://veglifekc.org/wp-content/plugins/super-forms/uploads/php/files//12517236874.pdfIn PDF document text
    • http://fritz-fahrlaender.ch/download/64936725447.pdfIn PDF document text
    • http://wf515345.tw/CKEdit/upload/files/bunilipewis.pdfIn PDF document text
    • http://phone-server.com/userfiles/file/vikifagirelugifupumube.pdfIn PDF document text
    • https://www.sadcmedia.com/wp-content/plugins/super-forms/uploads/php/files/ddckd2r0s935plddenqv3qjrff/84458795539.pdfIn PDF document text
    • https://www.baptistenhardenberg.nl/wp-content/plugins/formcraft/file-upload/server/content/files/1607c4d114da49---95452876671.pdfIn PDF document text
    • http://www.theagentpipeline.com/wp-content/plugins/formcraft/file-upload/server/content/files/160be06b660c75---90508225658.pdfIn PDF document text
    • https://nguoixunghekiev.vn/userfiles/file/97958480327.pdfIn PDF document text
    • http://mojahotels.com/ckfinder/userfiles/files/guvoruxejotejasuxobuj.pdfIn PDF document text
    • http://www.insurancedirectcanada.ca/wp-content/plugins/formcraft/file-upload/server/content/files/160a1bc3d4d69b---64526919369.pdfIn PDF document text
    • https://branchennachweis.eu/userfiles/file/98237341970.pdfIn PDF document text
    • http://grawerlik.pl/userfiles/file/97398163027.pdfIn PDF document text
    • https://xo-sound.ru/userfiles/file/30884878067.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/YTWXjIUwRh0/uplcv?utm_term=c%C3%A0i+zalo+cho+macbook+m1PDF 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_off0000e999.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE999 10452 bytes
SHA-256: 1f897a4c6001243da0fc4d318a9a550de094667df8ab383d907249b2c7c4b1f4
font_01_sfnt_off000100f0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x100F0 30732 bytes
SHA-256: cd20cabbddf9f70fc44af11156c6f1e5b080e44951efbeeae0fc02dae68d4ed4
font_02_sfnt_off00013b89.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13B89 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1