Malicious PDF — malware analysis report

Static analysis result for SHA-256 55126cbbc5baf0ec…

MALICIOUS

PDF

81.2 KB Created: 2021-09-07 04:16:50 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: c0fc7980f04949c612218e87740647ee SHA-1: ae5399a33af4079e2a88aa51bc15ec1a93f079a4 SHA-256: 55126cbbc5baf0ec9bbe29fa3725d7134ffc0bb1bdc3f65cedfef6183b6b0e66
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is identified as malicious by ClamAV and an ML classifier, with heuristics indicating it's a link farm on disposable hosting and potentially points to compromised CMS uploads. The embedded URLs suggest the PDF acts as a lure to external sites, likely for phishing or to download further malicious content. No scripts were extracted, but the PDF structure itself is used to host these malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

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://garglob.ru/uplcv?utm_term=ac+transient+analysis+pdf PDF link annotation
    • http://www.celso.org/download/62765807345.pdfIn PDF document text
    • https://40parables.com/wp-content/plugins/super-forms/uploads/php/files/e59f6e632b2049f7da97ca717c2a374a/48301907122.pdfIn PDF document text
    • http://kernenshepler.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/7776845632.pdfIn PDF document text
    • https://medicinasolidale.org/wp-content/plugins/super-forms/uploads/php/files/adfd843c5ead3df49417167968ce0166/53813906901.pdfIn PDF document text
    • http://55pluscommunityspecialist.com/userfiles/files/60508466117.pdfIn PDF document text
    • https://123kozijnofferte.nl/wp-content/plugins/super-forms/uploads/php/files/gkulg238nkqssh7d4kd6djb9h6/32659589184.pdfIn PDF document text
    • http://weingut-suppan.at/files/18901485679.pdfIn PDF document text
    • http://miydz.com/mingyi/images/userfiles/file/86818476831.pdfIn PDF document text
    • https://www.grandiosa.is/wp-content/plugins/super-forms/uploads/php/files/s0vq514jmkkm37bqa6r8bou462/91034713877.pdfIn PDF document text
    • https://storage-in-motion.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608adec664d91---6918932384.pdfIn PDF document text
    • https://www.dekleinewerf.nl/wp-content/plugins/formcraft/file-upload/server/content/files/1607449bb2c662---jobifibaxexurumes.pdfIn PDF document text
    • https://ahi.com.ua/wp-content/plugins/super-forms/uploads/php/files/c380dd3f5f6ccd76257a2921f5b93fd1/zobemasamasikakugumerupos.pdfIn PDF document text
    • http://www.fullertherapy.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608d1762893a9---biziropijegivorofeji.pdfIn PDF document text
    • https://przyklejki.pl/userfiles/segowatu.pdfIn PDF document text
    • https://xpress2.eu/ckfinder/userfiles/files/zijifemefevigowumogukige.pdfIn PDF document text
    • https://vydavatelstvoklett.sk/userfiles/file/damigijifepusopuge.pdfIn PDF document text
    • http://www.fashiongale.ro/userfiles/files/wajasurixakuromitamovo.pdfIn PDF document text
    • http://altelaw.com/uploads/image/file/jaxarix.pdfIn PDF document text
    • https://shinyjewellers.com/wp-content/plugins/super-forms/uploads/php/files/c84elu5di4fdhb5bjqn48ub41m/13924753161.pdfIn PDF document text
    • http://american-security-inc.com/assets/ckfinder/userfiles/files/jiwumavapesakexumibi.pdfIn PDF document text
    • https://dichocungtoi.com/userfiles/file/16313527835.pdfIn PDF document text
    • http://stellamaris.cz/userfiles/14705555261.pdfIn PDF document text
    • http://bulk-supplies.com/userfiles/file/sukuzozabosiwateru.pdfIn PDF document text
    • http://illinoislivestock.org/userfiles/file/lipivawan.pdfIn PDF document text
    • http://www.iamgoingto1996.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609b09a8bcb64---4474415979.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_off0000dbcf.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDBCF 10588 bytes
SHA-256: 4690acb55f4e4e4db3e459cfe6cc9dc68e377daaf1595ff7e86bb37b037126fa
font_01_sfnt_off0000f421.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF421 16472 bytes
SHA-256: 39e7ba92bbee9297f9fcb6dcafbd6ecd9df2681c5ea1d1b3ab68e101789534b6
font_02_sfnt_off00011f0f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11F0F 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1