Malicious PDF — malware analysis report

Static analysis result for SHA-256 a0cf3f533262beba…

MALICIOUS

PDF

75.0 KB Created: 2021-06-30 22:17:37 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: b81e347e9970c8711c85385d84146c47 SHA-1: 28acc428d48182da81217bfa2fb7a95691613fbc SHA-256: a0cf3f533262bebaad9c60232dc74a219092c1c3e3a1049fec138ddf8a228a35
156 Risk Score

Malware Insights

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

The sample is a PDF file detected as malicious by ClamAV and an ML classifier. It contains numerous links, many pointing to compromised WordPress sites, suggesting a link farm or phishing lure. The heuristic 'PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM' specifically indicates links to compromised upload storage, reinforcing the malicious intent. No scripts were extracted, but the document's structure and embedded URLs point towards an attempt to redirect users to malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9953

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://advicezone.org.uk/wp-content/plugins/super-forms/uploads/php/files/prhou9ch6kcsf627he51nngo48/fipuzoboluninipukav.pdf
    • https://www.rockandroll.blog.br/wp-content/plugins/super-forms/uploads/php/files/rb1u1m34rj4aom6jjbdmmf3o0g/borixubo.pdf
    • https://hssipm.com/wp-content/plugins/super-forms/uploads/php/files/d543bf165d3deebd52a7a02abe1f496f/99066647049.pdf
    • https://lakecountyoralsurgery.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c5ad0c407a9---mezefutinomofavalage.pdf
    • https://www.mozartcantat.nl/wp-content/plugins/formcraft/file-upload/server/content/files/160d00fd18d8cd---vuxoporizopime.pdf
    • https://vietnaminsight.biz/ckfinder/userfiles/files/sazaxikokelixabifag.pdf
    • https://sharzh-ufa.ru/wp-content/plugins/super-forms/uploads/php/files/96bd3527d94a7bc42ecae278ae6e24d9/rulagorekozaw.pdf
    • http://apsencollege.org/test/fckeditor/file/79638417151.pdf
    • https://www.taxikladis.gr/wp-content/plugins/formcraft/file-upload/server/content/files/1608ae393b084e---6247876597.pdf
    • http://woodsfamilypride.org/clients/2/2c/2c83419adcf4927d74d3defe18342386/File/ralofogisaw.pdf
    • https://www.hauptsache.cc/wp-content/plugins/formcraft/file-upload/server/content/files/160cbc3387b865---dixujifegudumawotomu.pdf
    • https://worldkelo.com/wp-content/plugins/super-forms/uploads/php/files/1b3471c01c46ef3203b1c4b9e76990ee/koson.pdf
    • http://bezagsecurity.cz/userfiles/94236968857.pdf
    • http://rymwid-training.com/userfiles/file/wagafojobomazupulidex.pdf
    • https://www.toptalentusa.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606d7ea15913c---wevikanoborojesu.pdf
    • http://kaowei.tw/image/files/20210527_012846.pdf
    • http://casier-a-bouteilles.com/file/63816429234.pdf
    • http://exactblue.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607c9eb43e789---11677220811.pdf
    • https://www.fmworks.com.tr/wp-content/plugins/super-forms/uploads/php/files/9oaa3hmk13b87q8de5gkqr73ko/palisonikilu.pdf
    • https://cafesca.org/ckfinder/userfiles/files/fazemozu.pdf
    • https://bostoncake888.com/UserFiles/files/91710073261.pdf
    • http://www.cuadernos.in/wp-content/plugins/formcraft/file-upload/server/content/files/1607131eeacf0b---21717534267.pdf
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/1KS0DP0cxss/uplcv?utm_term=asking+closed+questions
    • http://kioskcondoweb.wpengine.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b5ed34cfa72---wekekow.pdf
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000c54e.bin
1c261067d098227d656a400813f9edc65382174b816364ad3f37aca41e01f8a2
pdf-font-stream PDF embedded font (sfnt) at offset 0xC54E 16280 bytes
font_01_sfnt_off0000ef27.bin
627fb8d11b9dc1b4269c9d632ecd849f6a976efbf8403c745d07914b38e197e4
pdf-font-stream PDF embedded font (sfnt) at offset 0xEF27 10604 bytes
font_02_sfnt_off00010702.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x10702 16792 bytes