Malicious PDF — malware analysis report

Static analysis result for SHA-256 a55a4c95a151e8d7…

MALICIOUS

PDF

89.1 KB Created: 2021-07-04 21:19:35 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: d4624ebd0d6f8eba74c4424e24a058ec SHA-1: 2537e4b5d3221fe80f06fc002298e9634a8447dd SHA-256: a55a4c95a151e8d72388037b6668ebb5b8bd112603a1e2d6fcf4e83aa2b304d6
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a PDF file detected as malicious by ClamAV and an ML classifier. It contains numerous links to external websites, many hosted on compromised CMS platforms, suggesting a link farm designed to redirect users. The presence of PDF_SEO_DISPOSABLE_LINK_FARM heuristic indicates a tactic to manipulate search engine results or distribute malicious content. While no scripts were explicitly extracted, the nature of the links and the detection suggests a phishing or malware distribution vector.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9947

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://www.elementstraining.co.uk/wp-content/plugins/super-forms/uploads/php/files/6m3dmp0tvtfsviav3kjv13e450/sorobupupefirulesafapu.pdf
    • https://inchirierielicopter.ro/wp-content/plugins/formcraft/file-upload/server/content/files/160821c3a70dc9---96649988956.pdf
    • https://www.freshstartdigitalmarketing.com/wp-content/plugins/super-forms/uploads/php/files/59bae4dda634eccca6329d04d2999bca/sedanebitefojikonozewup.pdf
    • http://ecolservizinettuno.com/userfiles/files/wovatax.pdf
    • http://kaufdeinauto.de/wp-content/plugins/formcraft/file-upload/server/content/files/160a17f7e30839---totexewigapoku.pdf
    • https://www.mozartcantat.nl/wp-content/plugins/formcraft/file-upload/server/content/files/160788bafa3eef---37665166039.pdf
    • http://thephinhmienbac.com/upload/files/74066688484.pdf
    • https://dentinale.eu/wp-content/plugins/super-forms/uploads/php/files/c830945ee01266d51c6d4c6690b54dfa/64698742580.pdf
    • http://www.kissdocs.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/160ad94c351a76---75022933697.pdf
    • https://schreinerheusi.de/wp-content/plugins/formcraft/file-upload/server/content/files/1606f4a978d3f6---82335983537.pdf
    • https://gertiesbloomers.com/kousumi/nulook/upload/fckimages/file/20007140544.pdf
    • https://www.propertyadvisersaustralia.com/wp-content/plugins/super-forms/uploads/php/files/ae389c4287c06e465808742ec2ab1689/zirumijumelonutak.pdf
    • https://independentmusicleague.com/wp-content/plugins/super-forms/uploads/php/files/691d3a750643eb0a218ce1ad93d25436/73879238167.pdf
    • http://melissajacksonmd.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609b79782b665---sunininemopu.pdf
    • http://alpanelektrik.com/depo/sayfaresim/file/82034822016.pdf
    • https://laneopx.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607f9d43ab949---tezavokokozijogu.pdf
    • https://shrmivirtual.org/wp-content/plugins/super-forms/uploads/php/files/29260992887535b3eff1f075839066cb/xalotamesusukojezufor.pdf
    • https://www.keystonecare.co.uk/wp-content/plugins/super-forms/uploads/php/files/4c8cd9c17b237d33c50dd6c28a0a4705/nosegedefi.pdf
    • http://global-poseg.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609e01a922187---zezonuk.pdf
    • https://www.dolphinrfid.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608cb053100c0---letidozujoluka.pdf
    • http://www.cheapmotorcycleinsurancepa.com/wp-content/plugins/super-forms/uploads/php/files/jimhqa203enluui847cs594u51/40919650535.pdf
    • https://penal-garazh.ru/files/91385956972.pdf
    • http://dgjinhak.kr/DATA/upload/files/202106050325211173.pdf
    • https://rffsev.ru/wp-content/plugins/super-forms/uploads/php/files/272e1de3a5ab5adacf08ee3e8e667e1c/vadiwugagomagipojeminoxin.pdf
    • https://feedproxy.google.com/~r/Uplcv/~3/YTWXjIUwRh0/uplcv?utm_term=speed+up+surface+pro
    • 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_off0000f7fd.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xF7FD 16792 bytes
font_01_sfnt_off00011014.bin
cc3da433edb79ac9e1d0affb3d7f89004cf3102af96ea0d1922743555cf0a4eb
pdf-font-stream PDF embedded font (sfnt) at offset 0x11014 10448 bytes
font_02_sfnt_off000127d9.bin
6a0dcd693a51acc34ceba1ac7547285261075c12b88cb20d6bd41a9da0e56c9b
pdf-font-stream PDF embedded font (sfnt) at offset 0x127D9 17752 bytes