Malicious PDF — malware analysis report

Static analysis result for SHA-256 c4e1f53c5e782596…

MALICIOUS

PDF

68.8 KB Created: 2021-05-10 02:37:27 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-14
MD5: 52f48517d410a76e401d058d093f91a0 SHA-1: 081efaf8d84b75dfd2cb6530a75a4b0dcd6e13a1 SHA-256: c4e1f53c5e782596a88a25234e4e87efcc2a1507d78e90b7d844071f99f736e7
156 Risk Score

Malware Insights

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

The PDF file was identified as malicious by ML classifiers and ClamAV, indicating a high likelihood of malicious intent. It functions as a link farm, with numerous URLs pointing to compromised CMS upload directories, suggesting a phishing or malware distribution scheme. The document body is heavily obfuscated and contains metadata from wkhtmltopdf, but the primary threat lies in the external links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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 https://cananalimdar.com/wp-content/plugins/super-forms/uploads/php/files/0o5lup20naacttcf6gk4nh6uv3/zutusabixubagemip.pdf In PDF document text
    • https://uaqbakery.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607d81cb1f61d---70355237521.pdfIn PDF document text
    • http://mgmkt.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1607a16b2a0e5f---lokuzuvavupaj.pdfIn PDF document text
    • https://wills.sg/wp-content/plugins/super-forms/uploads/php/files/8b1b6216aaf638c19aeeef94d5edbb09/23062786671.pdfIn PDF document text
    • https://advicezone.org.uk/wp-content/plugins/super-forms/uploads/php/files/p3elf2uafsq3k35ll95hf7v3fj/10153651570.pdfIn PDF document text
    • http://www.skupp.pl/wp-content/plugins/formcraft/file-upload/server/content/files/1609665b3a83b9---dajagefaxakirati.pdfIn PDF document text
    • https://kvartira-zalog.ru/wp-content/plugins/super-forms/uploads/php/files/28b3e05b597c0d8356d2bfe214c26084/60980222823.pdfIn PDF document text
    • http://alsumiri.net/wp-content/plugins/super-forms/uploads/php/files/b879d00106fcc39a41a1f362c17dbb60/nukilofa.pdfIn PDF document text
    • http://www.inhd.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/16076172671cda---wotudepejuvit.pdfIn PDF document text
    • https://razvozka24.ru/wp-content/plugins/super-forms/uploads/php/files/d4c12164339afb1b38392488d96d08a8/jojiluvaloxukukujuve.pdfIn PDF document text
    • http://www.mondzorgvesa-voorschoten.nl/wp-content/plugins/formcraft/file-upload/server/content/files/16073804453b95---gukobekonujufebopikakew.pdfIn PDF document text
    • http://www.zopfitravel.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607510592e653---18234585374.pdfIn PDF document text
    • https://staffxrecruitment.com/wp-content/plugins/super-forms/uploads/php/files/a3e2a151cae5ea0645a3e9a90a92c582/sufefox.pdfIn PDF document text
    • https://harpethvalleypto.org/wp-content/plugins/super-forms/uploads/php/files/5f50b218d37bdc3c9d6602bb608cf366/25290586902.pdfIn PDF document text
    • http://fantasypartyentertainment.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607af60f35410---71215805470.pdfIn PDF document text
    • http://asja-doll.ru/userfiles/file/17334561966.pdfIn PDF document text
    • https://www.hadlowsecurityshutters.com/wp-content/plugins/super-forms/uploads/php/files/900862a2250b60d388cab9033c84aacb/vopepukanesone.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/BkSY9tpko7c/uplcv?utm_term=skyrim+creation+kit++sizePDF link annotation
    • http://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000d48e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD48E 5232 bytes
SHA-256: a9cb55307718a97c496b4c1cc1880e6dfa5281c6c5de153d8ff2b799c9bf8a20
font_01_sfnt_off0000e659.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE659 10792 bytes
SHA-256: 3ff1e1f9759df40846abb81228cb45d56830cbc2322b50cc1d689aac94b820c2